CCI Facilities; June 2019

Sentences are the building blocks of written English. Humans communicate more than ever through writing – and being able to write clearly can help you in your career as well as at university.  

Here we'll cover some basic sentence writing ideas and explore accessible, clear and grammatically-correct sentences in academic writing. You should use other resources to inform your writing too. 

This page may help you if your assignment feedback tells you to 'check your sentences' or 'take care with grammar', or if your feedback suggests the meaning of some of your sentences is unclear. 

What is a sentence?

In English, a sentence has to have two elements: a subject and a verb.

Here are some sentence examples:

  1. Most students work hard.
  2. This fact notwithstanding, some people believe, probably because of stereotypes in some popular media, that most students are lazy.
  3. This perception is wrong.
  4. Stereotypes persist.

Key points

  • the subject is the thing or person performing the verb (different to the everyday meaning of 'subject')
  • a verb is a 'doing' or 'being' word (such as ‘work’ in example 1, or ‘is’ in example 3)
  • a sentence can consist of just a subject and verb and still make sense and be perfectly grammatical (example 4)

Breaking down sentences

Most sentences contain a complement as well as a subject and a verb. In simple terms, the complement is ‘the bit that comes after the verb’ – in examples 1 and 3 above the complement is the words ‘hard’ and ‘wrong’. Adding complements to sentences often comes naturally to writers so you don't need to think about it consciously. 

Most sentences have three main elements:

  • [subject] [verb] [complement]
  • [something] [being or doing] [something]

For example: 

  • Most students work hard: [Most students] [work] [hard].
  • The clearest sentences are short and simple: [The clearest sentences] [are] [short and simple].

Even in a longer sentence with lots of extra information, you should be able to spot the main point of the sentence (something being or doing something). For example: 

  • [You] [should be able to spot] [the main point]. 

Sentences with more than one subject or verb

Sentences can contain more than one main subject and more than one main verb. Use conjunctions (words that connect complete ideas) to move on to the next idea in these sentences. The following sentence is an example of this:

Sentences with a single subject and verb may be clearest, but academic writing often necessitates longer sentences that explain relationships between ideas, so we are not suggesting that you use short sentences all the time.

Here’s that sentence broken down: 

  • [Sentences with a single subject and verb] [may be] [clearest],
  • but [academic writing] [often necessitates] [longer sentences] ...  
  • so [we] [are not suggesting] [that you use short sentences all the time].


  • [subject] [verb] [complement] [conjunction] [subject] [verb] [complement] ... [conjunction] [subject] [verb] [complement].

The conjunctions in the sentence above are ‘but’ and ‘so’. 

Remember to use conjunctions to write complex sentences with several subjects and verbs – or when there is more than one ‘something being or doing something’.

Key points to remember

Benefits of understanding sentences:

  • Knowing that sentences show ‘something being/doing something’ can help you to write clearly
  • Spotting the main subject(s) and verb(s) in your writing can help you improve your sentences when you edit your work.

Examples of good and bad sentences

Below are two versions of the same piece of writing. The sentences in the first example aren't grammatically correct or clear. The second example addresses the problems of the first, and is grammatically correct and easier to read. We've also explained some of the changes below the examples.

Bad paragraph example

There are a number of ways to impress your marker with your writing, perhaps the most important goal is the importance of writing clearly because clarity allows complex ideas to be understood. Shorter sentences are often the clearest, much clearer than long sentences. Which can easily ‘go wrong’. Because ideas can appear rather disjointed however it is probably in academic writing not wise to use too many short sentences – not fluent. So a mix of short length sentences and medium length sentences is probably best, shorter sentences can be used for key points in your argument, medium length sentences up to perhaps three lines in length can be used to develop ideas. This might of course vary though. Depending on your assignment.

Better paragraph example

There are a number of ways to impress your marker with your writing. Writing clearly is perhaps the most important goal. Clarity allows complex ideas to be understood. Shorter sentences are often much clearer than long sentences, which can easily ‘go wrong’. However, it is probably not wise to use too many short sentences in academic writing, because ideas can appear rather disjointed. As a result, the writing loses fluency. Thus a mix of short- and medium-length sentences is probably best, because shorter sentences can be used for key points in your argument, and medium-length sentences, up to perhaps three lines in length, can be used to develop ideas. This mix might vary, of course, depending on your assignment.

Paragraph breakdown

The first paragraph example uses a very long a first sentence, which is also repetitive (‘important’ and then ‘importance’). The second paragraph has used three sentences which each clearly stating 'one thing being or doing something' to do the same thing.

The second sentence of the bad paragraph uses: “Which can easily ‘go wrong’”. This is a fragment (not a full sentence) because it doesn't include a subject – what can easily go wrong? You should avoid using the word ‘which’ to start a sentence. The final sentence of the first paragraph is also a fragment. 

The third sentence of the first paragraph makes us wait for the subject ('it') and verb ('is'). In the second paragraph the subject and verb come immediately after the introductory word.

In the first paragraph, the sentence which begins “So a mix…” has three main points but the sentence ‘runs on’ and doesn't use conjunctions. This sentence in the second paragraph still has three main points, but is grammatically correct and uses the conjunctions 'because' and 'and'.

Do you want help with writing clear sentences?

We can help. Book your Academic Skills Unit (ASK) tutorial by emailing