Punctuation serves primarily to help show the grammatical relationships between words, but it is also used to indicate intonation. Its role is to clarify, and this principle takes precedence over all precepts governing the use of individual marks of punctuation. In the interest of clarity, punctuation should be as consistent as possible within a given text. For clarity, too, some grammarians recommend the use of "close" punctuation—the insertion of all punctuation, required or optional, which can be legitimately used. Most readers, however, will be grateful to the writer who opts for a more "open" style, omitting punctuation when this can be done without creating ambiguity. Finally, punctuation should not be a chore; if a passage appears difficult to punctuate, it probably needs to be rephrased.
Quotation marks are discussed extensively in Chapter 8 Quotations and Quotation Marks.
As a general rule, in English there is no space before and one space after a punctuation mark. Exceptions follow.
No space before or after a decimal period between numerals:
A space before and none after a decimal period not preceded by a numeral:
A space after a period following a person’s initial:
No space before or after a period in multiple numeration:
No space before or after a period when followed by a comma or a closing quotation mark, parenthesis or bracket:
No space before the periods following the capital letters in the official abbreviations of provinces and territories and no space after such periods except the last one:
A space before, between and after ellipsis points:
No space before or after a question or exclamation mark when followed by a closing quotation mark, parenthesis or bracket:
No space before or after a comma when followed by a closing quotation mark:
No space before or after a comma used to separate triads in numbers (see Note 2 in 5.09 Decimal fractions):
No space before or after a colon when used to express ratios or the time of day using the 24-hour clock, or to separate chapter and verse, volume and page, act and scene in references to books, plays, etc.:
One space before and none after an opening parenthesis or bracket within a sentence; no space before or after a closing parenthesis or bracket when followed by a punctuation mark:
No space before or between parentheses enclosing sections or subsections in citations from legislation:
No space before or after these marks when they are inserted between words, a word and a numeral, or two numerals:
No space before or after an oblique when used between individual words, letters or symbols; one space before and after the oblique when used between longer groups which contain internal spacing:
No space before or after an apostrophe within a word.
One space before and none after an apostrophe used to indicate omitted figures in dates:
One space before and none after an opening quotation mark within a sentence; no space before or after a closing quotation mark when followed by a punctuation mark:
The period marks the end of an affirmative sentence or sentence fragment:
The period is a "full stop." It stops the reader more fully than the colon, semicolon, comma or dash. Each of these marks of punctuation may, in many circumstances, be used in place of one of the others in order to lessen or intensify a break in the flow of the sentence or passage. In the following examples the period has replaced a weaker mark of punctuation in order to slow the reader down and focus his or her attention:
In the following examples, the period has itself been replaced by a weaker mark of punctuation in order to bring the elements into a closer relationship:
Use a period after a mild imperative or exclamation:
A sentence that is interrogative in form may be imperative in function and thus take a period (see 7.10 Requests, indirect questions and other uses):
Indirect questions are affirmative sentences and take a period, not a question mark (but see 7.10 Requests, indirect questions and other uses):
Use three ellipsis points (. . .) to indicate a silence in dialogue, hesitation or interruption in speech, a pause in narrative, or the passage of time. Used in this way, they are sometimes also referred to as suspension points:
Ellipsis points may be substituted for etc. and similar expressions at the end of a list:
Do not use ellipsis points to imply hidden meanings or to separate groups of words for emphasis, as is often done in advertising.
For the use of ellipsis points to indicate omissions in quotations, see 8.09 Omissions.
A row of dots (or short dashes), called leaders, is used in indexes and tables, including tables of contents, to help the reader align material separated by a wide space:
A series of dots is sometimes used in place of underlining to indicate where information (or a signature) is to be entered on a form:
Periods may replace parentheses after numerals or letters used to introduce items in a vertical list (see 7.67 Numbering):
A run-in sidehead should be followed by a period:
Do not use a period at the end of any form of heading (other than run-in sideheads), legend or the like, or after a date line or signature:
Short signboard messages do not require a final period:
Do not use periods with acronyms and initialisms and with abbreviations of compass directions (except in street addresses), degrees, memberships and distinctions, SI/metric unit symbols, chemical symbols or mathematical abbreviations:
A question mark is placed at the end of a direct question, sometimes even if the sentence is declarative or imperative in form:
A question mark may be used for each query within a sentence:
Opinions differ as to whether a polite request of the type May I . . . , Would you . . . or Will you . . . requires the question mark. However, a question mark will look out of place after longer requests of this kind, especially if the sentence embodies straightforward affirmative elements:
Although the question mark is normally omitted after indirect questions, one may be added if the sentence has the force of a request:
Occasionally a question will incorporate an exclamatory element. The writer must then decide whether the interrogative or the exclamatory element is to be given greater prominence:
A question mark in parentheses (italicized in square brackets in quoted material) is inserted after information about which the writer is uncertain:
Indicate missing digits with a question mark:
See Chapter 8 Quotations and Quotation Marks for the use of the question mark with quotation marks and other punctuation.
The exclamation mark is an intensifier. It is used to indicate surprise, urgency, finality and the like. It is most often found after interjections, but also after ellipses, contractions and inversions and after certain onomatopoeic words:
Sometimes the exclamation mark is used to convey a special intonation that the reader would not give the words if they were punctuated normally:
The exclamation mark is also used after forceful requests, wishes, invocations and commands:
An exclamation mark, usually in parentheses (italicized in square brackets in quoted material), is sometimes used to indicate incredulity on the part of the writer. As with the analogous use of the question mark, this is a technique easily overdone:
When exclamations occur in a series they are usually separated by commas:
However, two interjections may be combined with no intervening punctuation:
Where the words themselves suffice to convey the emphasis, or where the sentence or clause is more properly a question, do not use an exclamation mark:
Exclamations are of necessity short. An exclamation mark should never appear at the end of a long sentence unless it is intended to intensify only the last word or words.
The exclamation mark should be used as sparingly as possible. Emphatic wording is usually more effective than emphatic punctuation.
The comma is the most frequently misused punctuation mark, and many of the rules governing its use are vague and riddled with exceptions. The writer must frequently rely on personal judgment and should be guided by considerations of clarity more than by any particular set of rules.
Note that, as a general rule, commas interrupt the flow of a sentence and should therefore not be used where they do not contribute to clarity. A sentence requiring a large number of commas for clarity is probably a poorly constructed one in need of rephrasing. Yet the comma is also the mark most often incorrectly omitted.
Most difficulties with the use of the comma hinge on the distinction between restrictive and non-restrictive sentence elements. A restrictive word, phrase or clause adds to the words it modifies a "restrictive" or defining element that is essential to the meaning of the whole; it should therefore not be separated by a comma or other mark of punctuation. A non-restrictive element provides incidental or supplementary information which does not affect the essential meaning; it should be set off by a comma or commas.
(a) Introductory elements
There are exceptions to the general rule for punctuating restrictive and non-restrictive elements. An introductory phrase or clause, especially if it is a long one, is often followed by a comma even if it is restrictive:
Each of the above sentences could have been correctly punctuated with or without the comma. But an introductory subordinate clause is normally followed by a comma:
After introductory adverbs and short phrases indicating time, frequency, location or cause, the comma is omitted unless needed to avoid ambiguity or add emphasis:
Introductory adverbs or phrases used to mark transition or to express a personal comment are usually set off by commas:
The introductory phrase may also consist of an adjective or participle separated from its noun by the definite or indefinite article:
Conversely, it is sometimes possible to omit the commas that ordinarily set off non-restrictive elements, without obscuring the meaning. This is especially true of short adverbial expressions:
In such sentences the addition of commas not strictly needed for clarity gives emphasis to the elements thus enclosed:
(b) Absolute expressions
One form of non-restrictive expression is the absolute1 construction: a participial phrase grammatically unconnected with the rest of the sentence. Such phrases are followed by a comma:
Note the following errors in the punctuation of absolute expressions:
This common problem is avoided if the sentence is recast so that the subject of both clauses is the same:
(c) Parenthetic expressions
Parenthetic expressions are non-restrictive and therefore require commas:
If a parenthetic expression is removed from the sentence, the remainder of the sentence should read as a coherent, grammatically correct whole. For example, the sentence
is unacceptable because "as good . . . than" is incorrect English. The sentence should be recast as follows:
Occasionally it may be expedient to omit the first of the pair of commas around a parenthetic expression:
The parenthetic phrase here is "without realizing it."
Both commas can sometimes safely be omitted; under no circumstances, however, should the second comma be omitted while the first is retained:
Parenthetic expressions may be set off by parentheses or dashes instead of commas, depending on the degree of emphasis or pause desired, or the length of the expression. Compare:
A common error occurs with parenthetic phrases following the conjunction that. The comma that belongs after the conjunction is often placed before it instead:
Restrictive and non-restrictive appositives should be carefully distinguished. The latter are set off by commas, whereas the former are not:
As in the case of parenthetic expressions, the comma following a non-restrictive appositive cannot be omitted. Thus the sentence
is incorrect. A comma is required after "Gray."
Non-restrictive appositives in final position are usually preceded by a comma:
Often, however, the comma is replaced by a colon or dash:
If the appositive contains internal commas, it is best introduced by a mark other than the comma. In the following example, a colon would be an improvement over the comma after legacy:
(e) Annunciatory expressions
The annunciatory expressions namely, that is and for example are usually followed by a comma. They may be preceded by a comma, a dash, a semicolon or a period, or, together with the matter they introduce, may be enclosed in parentheses, depending on the emphasis desired:
The abbreviations i.e. and e.g.—although these are identical in meaning to that is and for example—should be preceded by a comma, a dash or an opening parenthesis, but need not be followed by a comma.
Note that the expression such as is used to introduce an example, not an appositive, and therefore is not followed by a comma. It may be preceded by a comma or other punctuation, as required in the sentence.
(f) Vocative forms
Vocative forms are non-restrictive and are set off by commas:
Similarly, exclamations and interjections are set off by commas (or exclamation marks):
Elements of equal rank or relation in a sentence are said to be co-ordinate. The co-ordinate elements may be words or phrases in a series, or they may be entire clauses.
(a) Nouns and noun phrases
Items in a series may be separated by commas:
They may also be linked by co-ordinating conjunctions such as and or or:
Opinions differ on whether and when a comma should be inserted before the final and or or in a sequence. In keeping with the general trend toward less punctuation, the final comma is best omitted where clarity permits, unless there is a need to emphasize the last element in the series. This comma is usually omitted in the names of firms and always before an ampersand:
On the other hand, it is usually inserted if the items in the series are phrases or clauses of some length, or if omission of the comma might lead to ambiguity or misunderstanding:
A comma is also required before etc.:
A more complex situation occurs when apposition commas are used together with co-ordinating commas, as illustrated below:
The sentence should be rephrased so that no non-restrictive appositive occurs within a co-ordinate element:
Alternatively, semicolons may be used to separate elements in a complex series (see also 7.23 The Semicolon, Co-ordinate elements):
A comma is normally used to separate two main clauses in a compound sentence when they are joined by a co-ordinating conjunction (and, but, or, nor, yet or for):
If the clauses are short or closely related, the commas may be omitted before and, but, or or nor:
Co-ordinate clauses not joined by a co-ordinating conjunction are usually separated by a heavier mark of punctuation than the comma:
A comma will suffice, however, if the clauses are short, or if the writer wishes to emphasize a contrast or lead the reader on to the following clause as quickly as possible:
When a number of independent co-ordinate clauses follow one another, a comma should be used after each one except (usually) the last, in accordance with the rule for items in a series (see 7.15 The Comma, Co-ordinate elements(a)):
It is a common error to confuse a simple sentence having a compound predicate with a compound sentence requiring a comma between clauses. Note the difference between the following examples:
Where the clauses of a compound sentence are joined by a conjunctive adverb (such as however, instead, meanwhile, otherwise, similarly, so, still, then, therefore or yet), a semicolon is usually called for, though a comma will often suffice before so, then and yet:
A series of adjectives modifying a noun may or may not be co-ordinate. The adjectives are co-ordinate if their order does not affect the meaning, in which case they should be separated by a comma. If they are not co-ordinate, that is, if one adjective modifies the phrase formed by the following adjective(s) plus the noun, then they should not be separated by a comma:
Adjectives of both types may of course occur together:
The rule stated above, however, is not an infallible guide. When in doubt omit the comma, as in:
The final adjective in the series should not be separated from the following noun by a comma:
(d) Antithetic expressions
Antithetic expressions are usually separated by a comma:
However, short expressions of this type may not require a comma:
Sometimes the reader will be led astray by a word or phrase which appears at first to be used in one sense but turns out from the context to be used in another. In all the following examples, commas should have been used in order to prevent misreading:
The comma can be a useful device for securing a pause or emphasis:
A comma may be used to indicate that words have been omitted:
Again, the comma may be omitted if clarity is not compromised.
Place a comma after words introducing short direct quotations, declarations and direct questions (a colon is needed to introduce longer sentences):
Note the capital letter and the absence of quotation marks in the last two examples.
If the quotation or question follows a form of the verb to be, is in apposition to a noun, or is worked naturally into the syntax of the sentence, no comma is needed:
It is also acceptable to omit the comma before quotations introduced by verbs of saying:
The use of punctuation in quotations is discussed in 8.03 Punctuation and grammar in run-in quotations.
Commas are used around titles and degrees within the body of a sentence:
A comma is placed between a surname and a given name or initials if the surname is written first:
Chinese and Vietnamese names are an exception. They are written with the family name first and no comma:
Use a comma to separate the day of the week from the date and the place from the date:
If the date is written in the order day-month-year, no commas are required before, after or between the components of the date:
If, however, the order given is month-day-year, the day and year are separated by a comma, and the year should normally be followed by a comma within the body of a sentence or sentence equivalent:
If you are stating only the month and the year, do not insert a comma:
Similarly, a comma separates a place name from the name of a province or the abbreviation for that province, and the province’s name or abbreviation is normally followed by a comma within the body of a sentence or sentence equivalent:
Use commas to separate address components, as illustrated:
Note that the postal code is followed, but not preceded, by a comma when the address forms part of a sentence, and that two spaces separate the provincial name from the postal code.
Do not use commas between the name and the number of an organizational unit:
Do not insert commas in numerical expressions such as the following:
The semicolon is used between independent clauses not joined by a co-ordinating conjunction but too closely related to be separated by a period:
If the clauses are short and parallel, a comma may replace the semicolon:
Clauses joined by a co-ordinating conjunction may also be separated by a semicolon (instead of a comma) if they are the last two of a series of clauses separated by semicolons:
Use a semicolon if a sharper break is required than could be achieved with a comma (for emphasis or to convey antithesis):
Clauses joined by a conjunctive adverb usually require a semicolon between them, though a comma may suffice if the clauses are short:
Elliptical clauses are conventionally separated from each other and from the introductory clause by semicolons, with commas often marking the ellipsis (see 7.17 Omitted words):
The semicolon can be replaced by a comma, however, provided that the comma marking the ellipsis can be dropped:
Semicolons may be used in place of commas to separate parallel elements in a series if these elements are complex or contain internal punctuation, or if greater emphasis is desired:
Even a series of parallel subordinate clauses may be separated in this manner, provided that the resulting punctuation is not apt to confuse the reader.
Although most writers tend to underuse rather than overuse the semicolon, a writing style that employs a large number of semicolons is likely to be heavy and dull. Consider using the dash, colon or comma instead.
The colon may be used between two independent clauses not joined by a conjunction if the second clause explains, illustrates or enlarges upon the first. In such sentences a semicolon would also be correct, but less effective:
A colon may be used between two clauses in antithesis:
The work of the colon could have been done by a period or even a comma in the above example.
The colon is used primarily to introduce the words that follow it. It introduces a formal quotation or a formal statement:
Short quotations or declarations, however, are usually introduced by a comma (see 7.18 Quotations, etc.).
The colon is also used for the question-and-answer format, to introduce dialogue and in transcriptions:
The colon introduces a list, but should not be used after "such as," "for instance" or "for example," or if the list is the object or complement of an element in the annunciatory statement:
In cases such as the last two, use no punctuation after the annunciatory statement or insert a phrase such as "the following," "as follows" or "as illustrated," which then takes a colon.
The colon can be used to introduce vertical lists, even if the series is a complement or object:
The teleworking issues before the working group included:
However, here too, an introductory phrase ("the following," etc.) is preferable.
In business letters and printed speeches, a colon follows the salutation:
In personal letters, the colon is usually replaced by a comma:
The colon is used to separate titles from subtitles. It is followed by a single space:
In references to books, plays, etc., colons separate chapter and verse, volume and page and act and scene, with no space on either side of the colon:
Location and name of publisher are also separated by a colon. The colon is followed by a single space:
See Chapter 9 Reference Matter for further information on the use of the colon in reference matter.
See Chapter 5 Numerical Expressions for uses of the colon with numerical expressions.
Do not use a colon followed by a dash (:—).
Do not place a colon at the end of a title or heading standing on a separate line from the text it introduces.
Parentheses, or round brackets, are used to enclose additional information serving to explain, amplify or provide comments on adjacent material. Commas and dashes are also used for this purpose (see 7.14 Restrictive/non-restrictive(c), 7.42 Interruptions, pauses, afterthoughts, clarifications and emphasis and 7.44 Material in apposition). Parentheses, however, are generally used for words that are less closely related to the rest of the sentence than material which would be set off by dashes or commas. They are also more convenient for parenthetic elements which run to some length or contain internal punctuation, although it is best to avoid lengthy parentheses wherever possible.
Parentheses may save the writer from other punctuation problems, such as the confusion created when apposition commas and enumeration commas appear together, as illustrated below:
A parenthesis consisting of a complete sentence does not take an initial capital and final period unless it stands alone between complete sentences:
An opening parenthesis should not be preceded by any other mark of punctuation unless the parentheses are being used to enclose numbers or letters of enumeration (see 7.35 Letters and numerals):
After the closing parenthesis, any punctuation which would be appropriate in the absence of the parenthesis should still be used:
Before a closing parenthesis only a period, question mark, exclamation mark or quotation mark is permitted:
Parentheses de-emphasize the words they contain, which often take the form of an afterthought or aside:
An important afterthought, however, should be preceded by a dash or other mark of punctuation:
In transcripts, use parentheses to enclose information on one of the speakers:
Parentheses should not alter the flow of the sentence in which they are inserted; the rest of the sentence should make sense if the parenthetic element is removed. The following is incorrect:
If you cannot avoid placing parenthetic material within other parenthetic material, use square brackets within the round brackets (see 7.37 Use within parentheses) or use a combination of parentheses and em dashes:
In legal texts, parentheses are used to enclose numerals previously written out:
Individual letters or groups of letters may be enclosed within parentheses:
Numerals or letters of enumeration may be enclosed in parentheses (or be followed by a period):
Square brackets, often simply called brackets, are more disconnective than parentheses. They are used to enclose material too extraneous for parentheses. Use brackets for editorial comments or additional information on material written by someone else. To use ordinary parentheses for this purpose would give the impression that the inserted words were those of the person quoted. Square brackets should also enclose translations given immediately after short quotations, terms and titles of books or articles. See 8.14 French and foreign-language quotations for detailed information and examples.
When one set of parentheses is to be placed within another, replace the inner parentheses with square brackets (though dashes may be used instead—see 7.33 Parentheses within parentheses). Parentheses within parentheses should be used sparingly, however, except in legal and scholarly texts and specifically for letters and numerals referring to subsections of a document:
Square brackets may also be used in place of round brackets where two or more sets of the latter would otherwise occur in succession:
Braces are used to link two or more lines of writing:
They are also used to group items in formulas and equations. See 7.39 Multiples.
In mathematical usage, the preferred order for multiple brackets is as follows:
Note that square brackets enclose round brackets, in contrast to the practice in non-mathematical usage.
In most of its uses the em dash ("long dash") is a substitute for the colon, semicolon or comma, but it indicates a more emphatic or abrupt break in the sentence, or a less formal style.
Use a dash, not a colon, to enclose a list of terms that does not end the sentence:
Like parentheses, a dash may be used at the end of an unfinished or interrupted statement or a pause, as in transcripts:
Here the dashes are used to indicate, first, a pause and clarification and, second, an interruption.
The dash may be used to introduce an afterthought, correction or repetition:
It may similarly be used to set off an emphatic ending or one that contrasts with the remainder of the sentence:
Dashes give greater emphasis to parenthetic material than do commas or parentheses. If the parenthetic material contains internal punctuation or forms a complete sentence, the commas that might have been used to enclose it should be replaced by dashes or parentheses, depending on the degree of emphasis desired or the closeness of the relationship to the rest of the sentence. Parentheses are generally used to enclose material more remote from the main thrust of the sentence, dashes for material more closely related:
The em dash is also used to attribute a quotation, as in the example above.
A dash is sometimes inserted before the final portion of a sentence to clarify its relationship to the rest of the sentence, often with the help of a summarizing pronoun such as all or these or with the repetition of key words:
Explanatory material in apposition may be set off by dashes to secure greater emphasis than would be achieved with a colon or commas or to avoid confusion with commas within the apposition:
A dash may be used to separate the heading of a chapter or the like from the description of its contents or to separate subheadings within a chapter or section, as in a catalogue:
It is sometimes used in place of bullets, numerals or letters in vertical lists:
It can represent nil or unknown in a list of figures:
|Element||Atomic weight||Density||Melting point|
Do not combine the dash with any mark of punctuation other than quotation marks, the question mark, the exclamation mark and occasionally the period. In particular, do not use the colon-dash (:—) to introduce a quotation or a list.
Use the en dash ("short dash") to join inclusive numbers:
Use the en dash to join the names of two or more places:
The hyphen is used in certain compound nouns, adjectives and verbs, and to join prefixes to proper nouns. It is also used in word division at the end of a line. See 2.17 Word division.
Use the hyphen to spell out a word:
Hyphens also indicate slow, deliberate enunciation:
For use of the hyphen with numerical expressions, see 2.10 Numerals and units of measurement, 2.11 Fractions, 2.15 Numerals and single letters, 5.05 Adjectival expressions and juxtaposed numbers and 5.08 Fractions.
The oblique is also known as a solidus, slant (line), bar, virgule, diagonal, stroke or slash.
Do not use the oblique instead of a hyphen at the end of a line of ordinary prose to indicate word division.
The oblique is used in certain abbreviations:
It can be used as a symbol for per:
Do not use the oblique to represent per more than once in a single expression:
Do not use it with expressions of quantity written out in full:
The oblique is sometimes used in fractions, especially when set into running text, or when they would be ungainly in the form given below:
Use it with ellipsis points and a numeral at the lower right-hand corner of a page to indicate that the text continues on the following page:
An oblique may indicate alternatives:
A similar use is seen in bilingual titles such as L’Actualité terminologique / Terminology Update.
The expression and/or may be redundant and should be used with caution:
Oblique strokes may separate headings on a form:
The oblique is used increasingly to indicate complex relationships between words, a role traditionally filled by the hyphen:
The primary use of the apostrophe is to indicate possession. A word which does not end in a sibilant (s or z sound) forms the possessive by the addition of ’s:
To form the possessive of French words ending in a non-sibilant s or x, add an ’s:
Note that it is the pronunciation, not the spelling, which determines the possessive form. The word conscience ends in a sibilant; Illinois does not. Plural forms which do not end in a sibilant are no exception to the general rule:
Plurals ending in a sibilant take only the apostrophe:
Regarding the appropriate form for singular words that end in a sibilant, pronunciation is again the determining factor. If it would be natural to pronounce an extra s, add ’s; if an additional s would be difficult to pronounce, add only an apostrophe:
Since awkwardness of pronunciation is the basic criterion, the decision to add or omit a possessive s ultimately depends on the writer’s own sensitivities. One option is to rephrase:
With inanimate "possessors," especially abstract concepts, the apostrophe is generally not used to denote possession. Use an "of" construction instead:
However, certain expressions of time and measurement do take the apostrophe:
Figurative compounds of the sort bull’s-eye or crow’s-nest retain ’s in the plural:
When the possessive of a compound noun or a noun phrase is formed, add ’s to the last word only, unless there is a possessive relation between the words within the phrase itself:
If possession is shared by two or more subjects, add ’s to the last word only:
To indicate individual possession, ’s is added to each element in the series:
The apostrophe is often omitted in geographical names:
Note also Saint John (city in New Brunswick) and Hudson Bay—but Hudson’s Bay Co. Consult the Gazetteer of Canada when in doubt.
The ’s is often omitted in names of institutions, especially in the case of plural nouns that are adjectival rather than strictly possessive:
The official or customary form should be used, whatever it may be:
Note that there is no apostrophe in the possessive forms yours, hers and its. It’s is always a contraction of it is. See also 12.03 Words commonly misused or confused.
Apostrophes represent omitted letters in contractions or omitted numerals in dates:
Certain plurals are sometimes written with ’s:
Another solution is to italicize the letter, symbol or numeral in question (see 6.11 Mathematical, statistical and scientific material).
an overabundance of is’s and which’s
It is not necessary to use the apostrophe in set expressions such as "the dos and don’ts," "no ifs, ands or buts," "the whys and wherefores."
Vertical lists can be punctuated in a number of ways, but the writer should ensure that punctuation is consistent throughout the text.
The colon is generally used to introduce vertical lists. When the sequence of a list is random or arbitrary, the various elements may be simply indented or set off with bullets or em dashes:
These factors should determine committee size:
Numbers and letters, enclosed in parentheses or followed by a closing parenthesis or period, are used to introduce items in lists where precedence or sequence is important:
The tasks assigned to the committee are as follows:
(a) setting up safety programs
(b) monitoring the programs
(c) dealing with employee complaints
(d) maintaining complete records
(e) making recommendations
Punctuation can be omitted after each item if the items are brief. Otherwise, a comma, semicolon or period is generally used.
Use a semicolon after each item (and a period at the end of the list) if one or more items contain internal punctuation, or after each item of a list ending in and or or, even if the items contain no internal punctuation:
The Bureau has set the following priorities for the coming year:
Items made up of sentences should begin with a capital letter and end in a period (or question mark):
The following factors affected grain yield:
Practice regarding capitalization of items in vertical lists varies. The first word of each item is usually capitalized when the item is a complete sentence or when the annunciatory statement is a complete sentence.
The first word of each item is usually lower-cased if the items in the list are syntactically linked to the introductory statement, especially if the list is not introduced by a colon:
This versatile program can be applied to
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