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1.31 Effective punctuation

Good, correct use of punctuation is very important in your writing. Punctuation often plays the same role as variations in your voice do when you are speaking: full stops, colons, semi-colons and commas indicate various lengths of pauses; a question mark obviously indicates a question, whereas a rise or fall in your voice would do this. Lack of punctuation, therefore, or incorrect use of it, will result in your writing being difficult to follow, and your reader having to do unnecessary work. It could, in fact, be argued that correct punctuation is more important than correct grammar in making your writing easy to read.

Here are the names of the different types of punctuation, followed by notes on each.

[ . ] full stop
[ , ] comma
[ ; ] semi-colon[ : ] colon
[ ? ] question mark
[ ! ] exclamation mark [ " " ] quotation marks
[ ' ] apostrophe
[ ( ) ] brackets[ _ ] dash
[ / ] forward slash

Full stops

These obviously indicate the end of a sentence and must always be followed by a CAPITAL letter. Make sure you don't split a sentence unnecessarily with a full stop, creating what are known as sentence fragments.


The biggest punctuation problem is the incorrect use of commas: not using them, or using them in the wrong place. Remember that commas should be used to indicate to your reader a break in the flow of writing. If you write a long sentence without commas, then it may be very difficult to follow.


Semi-colons create a break in a sentence somewhere between a full stop and a comma. If you're unsure about their use, don't worry: it's never necessary to use them. They are used to connect sentences with very similar meanings or which are closely linked; in the following examples, however, the sentences could be written separately, or connected with a word like whereas:

Economics is regarded as a Social Science; Engineering is an Applied Science.
It is a thriving department; cuts in funding do not seem to have had an effect on them.

Semi-colons can also be used to separate long items within a list:

A balanced diet such include regular intake of carbohydrates, such as pasta or bread; fruit and vegetables, preferably fresh and ideally organic; meat, although excessive intake of red meat should be avoided; ...


Colons can be useful to add flexibility and variety to your writing, but it is rarely (or never) necessary to use them. They are perhaps most frequently used to introduce a long list, table or figure; or maybe a long quotation separated from the rest of your text. Shorter quotations are preceded by a comma. They might also introduce some examples:

The data is presented here in tabulated form:

According to Cook (1997):
Corpora are only partial authorities. The cumulative language experience of an individual, though less amenable to systematic access, remains far larger and richer. Even a three hundred million word corpus is equivalent to only around three thousand books, or perhaps the language experience of a teenager.

Colons may also be used to separate date and page number in a reference: (Caddick, 1999:56).

Question marks

These always come right at the end of the question sentence. Remember, though, that too many direct questions are best avoided in academic writing; indirect questions do not need a question mark.

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Exclamation marks

Unless quoting what someone has directly said to you in an interview, avoid using exclamation marks in your academic writing. They are too informal.

Quotation marks (inverted commas)

Don't worry too much about whether to use single or double marks, but do make sure you are consistent in your use. They can be used to indicate that a word is being used in a special way; perhaps if you are being ironic, or making a simile, or simply naming something:

Ganguly (1988) described the process as 'asymmetric'.
The behaviour of the English 'supporters' was despicable.

This could also be done by using italics.

Their main use, of course, is in quoting. Guide 1.28 contains examples. Just one point: if you do make a quotation, make sure you put quotation marks at the end of the quote. It's surprising how many people forget to!


A lot of native English speakers are getting very confused about the humble little apostrophe.
Apostrophes have two distinct uses in English:

To indicate possession
To indicate a missing letter or letters in a contraction

Note that apostrophes should only very rarely (if ever) be used to indicate plurals - see note below:


An apostrophe is used to indicate possession - that something belongs to somebody or something. For example:

The committee's decision (=the decision of the committee)
The President's mistake (=the mistake of the President)

If the person's name ends in '-s', you can write:

Charles' ears or Charles's ears

In these examples, there is only one committee, one President and one Charles, so the apostrophe comes before the '-s'. If we want to indicate that something belongs to more than one person or thing, then the apostrophe comes after the '-s':

The students' representation (=the representation of the students)

Note the use of the apostrophe in the following:

in three hours' time (literally, in the time of three hours)

The possessive pronouns its, ours, yours and theirs do NOT have an apostrophe:

Its performance is second to none
I like their garden: in fact, I prefer theirs to ours.

(You will, however, see widespread confusion between the use of 'its' and 'it's', even in the press, advertisements, official documents and product packaging. See newspaper articles below.)

You would not normally say something like 'the car of John'. This type of expression, however, is used when expressing 'important' or 'official' ideas' hence:

The Queen of England (NOT England's Queen)

Sometimes both might be possible, for example:

The Court's decision or The decision of the Court.

The latter, however, sounds more sombre or momentous.

Note also that English often puts nouns together, which in some cases would also indicate possession:

The findings of the report or The report findings

Things get a bit complicated here, so if you're not sure, consult a good dictionary.


In spoken English and informal writing, contractions (e.g. I've) are extremely common: you will in fact sound very strange if you don't use them when you're speaking. The apostrophe indicates where the missing letters should be:

there's = there is
he's = he has or he is

IMPORTANT NOTE: Contractions should NOT be used in formal academic writing. Always write out the full form of the words


Apostrophes are only used in plurals in one or two special cases (see below). In recent years, however, in this country, and also in other English speaking countries such as Australia and the USA, we have seen the emergence of what is sometimes called the"greengrocers' apostrophe": the use of the apostrophe to show a plural, as in:

Apple's 40p a pound

This misuse is extremely widespread now, making people even more and more confused, and may even lead to some sort of permanent change in the language. This is no excuse for you to make this mistake, though! So apart from the odd examples below, DO NOT use apostrophes for plurals!

An apostrophe can be used for the plural of abbreviations such as PC's or CD's, but even here it is not necessary. PCs or CDs look better. The only case where you do need an apostrophe for the plural is with special words and expressions which are not usually found in the plural (and as such should probably not be used in your writing). For example:

No if's or but's, get off to bed now!


Apart from in references, it is best to try to avoid brackets. Their use is bad style, they can make your writing difficult to follow, and are never necessary. Commas usually serve exactly the same purpose.


Don't use them; they are too informal.

Forward slashes/strokes

Apart from internet addresses or other special uses, don't use them. Instead of cities/towns/villages you should write something like cities, towns or villages.

Links to further resources on punctuation

English for Academic Purposes
Bristol University



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Steve Gould
Last updated: 4 January 2011

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