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Write: Grammar

Grammar & Punctuation
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Sentences Paragraphs Apostrophes
Commas Semi-Colons Colons



Let's will look at how different types of sentences are constructed and how to use punctuation correctly. A sentence provides the framework for the clear written expression of our ideas. They always begin with a capital letter and end with one of the following:

  • full stop
  • exclamation mark
  • question mark

A complete sentence always contains a verb and expresses a  complete idea. It makes sense on its own. To check that you are writing complete sentences, try reading them out loud. Pause when you come to a comma or full stop. Can each sentence stand alone as a complete thought? If you need more information to complete the idea, the sentence is not right.

Examples of good and bad sentences
Below are some examples of good and bad sentences with explanations.

Good: Andy reads quickly. 
This is a complete sentence. It contains a verb, which is reads. It expresses a complete idea because you don’t need any more information to understand it.

Bad: When Andy reads.
This is an incomplete sentence because we need more information to complete the idea of what happens when Andy reads.

Good: When Andy reads, he reads quickly.
This is a complete sentence because it expresses a full idea.

Bad:There is another theory. Which should not be ignored.
The second sentence doesn’t stand alone as a complete thought.

Good: There is another theory which should not be ignored.
The sentence makes sense.

Bad: The proposal was finally rejected. Although they considered it.
The second sentence doesn’t stand alone as a complete thought.

Good: Although they considered the proposal, it was finally rejected.
The sentence makes complete sense.


Sentences are made up of clauses, which are groups of words that express a single idea. There are two types of clauses:

  • Independent clauses – these stand alone as complete sentences.
  • Dependent clauses – they need an independent clause to complete its meaning.

A dependent clause always needs to be combined with an independent clause to complete an idea. Clauses make up different types of sentences - simple, compound, complex and compound-complex. 

  • Simple sentences: They are made of just one independent clause and need only one punctuation mark at the end.
    •     eg The assignment was late.
  • Compound sentence: They are made by joining simple sentences. Joining closely related sentences makes the writing flow. Joins are made by using a comma or the words and, but, so, or yet 
    •      Example: The essay was late, so he lost marks.
    •      Example: The essay was late; he lost marks.
  • Complex sentence: This is a sentence that is made by joining an independent clause with a dependent clause.
    • Example: Because his assignment was late, he lost marks.

Commas in sentence clauses
The comma separates the dependent from the independent clause because the dependent clause comes first. 
Common words that start a dependent clause include although, as, because, even though, if, instead, through, when whenever, where, and while.

  • Example:  He lost marks because the assignment was late.

The independent clause comes before the dependent clause so it doesn't need a comma.

Compound-complex sentences
This is a sentence in three parts. A dependent clause begins the sentence, it is separated from the central clause by a comma and then the end of the sentence is an independent clause.

  • Example: When considering owning a pet, you must calculate the cost, or the animal may suffer.

Make your writing flow
Use different types of sentence structures to make your writing flow. Below is an example of writing that contains correct sentences but the writing doesn’t flow:

  • Jackie is confident. She is a good speaker. She is considered to be an excellent presenter. Everyone finds her interesting. No one has been critical. She is supportive of others.

The writing flows better if you combine some of the sentences that are closely related:

  • Jackie is confident, she is a good speaker. She is considered to be an excellent presenter. Everyone finds her interesting, and no one has been critical as she is supportive of others.

Below is a sentence that is long and complicated:

  • If you consider buying a puppy, whatever age or breed, always consider the type of house you have, as this is the most important first step, because without considering this first you can find yourself with a dog that, despite your good intentions, you just cannot keep.

This sentence should be shortened so the writing flows, but you must to avoid confusing the reader:

  • If you consider buying a puppy, whatever age or breed, always consider the type of house you have. This is the most important first step. Without considering this first, you can find yourself with a dog that you just cannot keep, despite your good intentions.

Sentence tips:

  • Read your sentences aloud to see if they make sense.
  • Check that each sentence stands alone as a complete idea.
  • Break long sentences into shorter sentences.
  • Join abrupt sentences together to make the writing flow.
  • Vary the length and type of the sentences you use.
  • Check your punctuation.


Paragraphs divide writing into a number of points or stages. Each paragraph should deal with one idea or one aspect of an idea. It should be clear to the reader what the main idea is.

If used correctly, paragraphs create a clear written structure. A paragraph is a chunk of writing of any length. As a general rule they should not be less than 2 or 3 sentences, and there should be 2 or 3 on an A4 page.

Paragraphs are separated by a blank line or they are indented a few spaces. The end of a paragraph creates a pause in the flow of your writing. This pause tells the reader that the writing is about to move on to a different idea or a different aspect of an idea.

When you begin a new paragraph you should be clear about the main idea you are covering. Check that you don’t go off on a tangent, discuss details that would work better in a different paragraph, or discuss details that need a paragraph of their own.

Paragraphs often have a brief introduction and conclusion. The introduction of a paragraph makes the purpose of the paragraph clear to the reader. It often explains how that idea is relevant to the main topic. The main body of a paragraph should develop this idea. An idea can be defined, examples provided, commentary can be given, opposing ideas can be discussed, and implications and consequences can be shown. The conclusion of a paragraph links back to the introduction and comments on the implications of the point as a whole or makes a link to the next paragraph. Don’t end the paragraph with brand new or irrelevant detail. 

Paragraph summary:

  • Paragraphs provide a structure that enables the reader to follow a thread of ideas.
  • Paragraphs have their own internal structure but they need to fit into a larger piece of writing.
  • Be clear about the idea or argument that you cover in each paragraph.
  • Check that the first line of a paragraph outlines the paragraph’s main idea.


An apostrophe looks like this ' it has two main uses:

  • It replaces missing letters when we join two words together eg cannot becomes can’t. This is called a contraction.
  • It shows ownership eg John’s book

Contractions: They replace one or more letters, which creates a shorter word:

  • Do not   becomes   don’t
  • I will   becomes   I’ll
  • You are   becomes   you’re
  • They are   becomes   they’re
  • Were not   becomes   weren’t
  • Cannot   becomes   can’t

As you progress through your studies you should use them less and less in assignments.

Ownership: This is when an apostrophe is used to show ownership and make a word possessive. There are 3 ways to do this.

1. If the word is singular you add: ’s
    eg the student’s book    means that the book belongs to the student
    eg the boss’s armchair  means that the chair belongs to the boss
    eg John’s dog means that the dog belongs to John

2. If the word is a plural but does not end with a “s” you add: ’s  
    eg women’s rights   means the rights of women
    eg men’s toilet   means toilets for men

3. If the word is a plural that ends with an “s” you add: ’
    eg the students’ library books   means the books that belong to a group of students
    eg the womens’ football league   means a women only football association
    eg the workers’ rights   means the rights of a group of workers

Common problems with apostrophes
Some words frequently cause problems and confusion. They are its / it’s  and whose / who’s.

Its - belongs to a group of words that are already possessive. Others include his, hers and yours. Because they are already possessive they don’t need an added apostrophe. This means that the sentences below indicates ownership even though it doesn’t contain an apostrophe:

    eg The school ignored its rules for one day.
    eg The government abandoned its policy.

It’s - contains an apostrophe because doesn’t indicate ownership. The apostrophe tells us that the words it and is have been shortened into the one word it’s.
    eg Its a nice day.

Whose - is another word that is already possessive. This means that you don’t need to add an apostrophe to indicate ownership.
    eg The student whose notes I borrowed is angry with me.

Who’s - contains an apostrophe because doesn’t indicate ownership. The apostrophe tells us that who is has been shortened to who’s.
     eg The student whos coming to visit is lovely.

Apostrophe tips:

  • Just because a word ends in an “s” doesn’t mean that it needs an apostrophe.
  • An apostrophe is added to show ownership/possession or it indicates that a word or two words have been shortened.


Commas look like this , They can help your writing be easily understood. They divide or separate parts of a sentence to make the meaning clear.  A comma marks a brief pause in the sentence, usually at a point where you would naturally pause if you were reading out loud. 

Commas can be used to separate words or phrases that together make up a list.
    eg The fish kept in the ponds were pike, perch and carp.

Commas can be used to separate an introductory word or phrase in a sentence.
    eg Nevertheless, many critics see value in this theory.
    eg After the first decade, the changes were fully integrated into the system.

A comma can separate a word or phrase that briefly interrupts the flow of a sentence.
    eg The same theory, according to most writers, can be applied to language acquisition.

A comma can separate an afterthought or a final phrase that contrasts with the main part of a sentence.
    eg The war was vitally important for Europe, far more than it was for America.

Commas can link short and simple sentences if you add a coordinating conjunction or word such as and, but, so, or , nor and yet. A comma cannot join two sentences on its own because a comma only indicates a pause. You need to add a comma and a coordinating conjunction to join sentences properly.

eg The university is large, and it is close to the town center.

Comma tips:

  • Read each sentence aloud and pause briefly at each comma. If the sentence flows badly and seem jerky, you probably have too many commas. If you are breathless at the end of the sentence, you might need to add a comma.
  • It is a good idea to divide a long sentence into two or more separate sentences.


A semi-colon looks like this ;  It has two uses- It can link sentences or separate items in a list.

Linking: A semi-colon can mark a break which is stronger than a comma but less final than a full stop. Using a semi-colon to link related or closely linked sentences emphasises their relationship and varies the pace of the writing.

    eg  I read the book in one evening; it was not very helpful.
eg He was nervous about giving the speech; he asked for water several times.

A semi-colon can also be used to link sentences that include connecting words such as otherwise, however, therefore, moreover, nevertheless, thus, besides, accordingly, instead and consequently.

    eg I did not finish reading the book; instead, I watched the TV.

Lists: A semi-colon is used to separate items in a list, when that list contains one or more commas. It reduces confusion.

    eg The three venues will be: Middleton Hall, Manchester; Highton House, Liverpool; and the Ashton Centre, Sheffield.
eg The main points in favour of the new system were that it would save time for buying, accounts and on-site staff; it would be         welcome by the reception staff; and it would use fewer resources.



A colon looks like this : They create a pause and indicates that the reader should look forward to information that follows on from the last statement. It can be used to introduce a list or introduce an explanation.

Lists: A colon can indicate that a list is about to follow.

    eg Topics discussed included: the structure of viruses, virus families and current research.
eg Students joining the department must attempt to: attend all classes, meet deadlines  and join in class discussions.  

Explanations: A colon can be used to introduce a conclusion, a clarification of an earlier statement or an explanation. The colon separates and highlights the second statement, showing that it follows on from the first.

    eg Yoga is more than a form of exercise: it is meditation in movement.
    eg After much research, the teacher came to a final conclusion: development could not take place without more funding.

The colon and the semi-colon are often underused because many people aren’t sure how to use them correctly. Both can make your writing easier to understand and prevent an overuse of commas and full stops.

[The text above is based on that provided by the University of Leicester]

Grammar Tips