Sentence structure

Sentence structure

How do I make a great sentence? What types of sentences are there in English? Learn about sentence structure in academic English.

This blog post expands on the information from the previous blog's video on Sentence Structure. Watch that video for more detail on making sentences. 

What's in an English sentence?

In a correctly formed sentence, there will be one or more clauses. If there is more than one clause, there will be linking words, each of which allows you to add one more clause or dependent phrase into your sentence. We'll look more at clauses later.  

How long should my sentences be?

Great question with no easy answer. Generally, in English there is a preference for short, simply-formed and direct sentences. The average English sentence length is 10-15 words. An example of this is in the well-known Harry Potter books, where the average sentence length is 12 words. However, measuring length can also depend on word length (i.e. how many letters or characters in each word) and syllable length (how many syllables in each word). If there are 'longer' words in this sense, a shorter sentence may be better to increase 'readability'. What's that!? It simply means how easy it is to read something. 

In academic English, sentences will often be a bit longer because you may need to explain complex relationships between information. Guides often cite 15-20 words as an optimum sentence length in academic writing, but if you are using longer or more complex vocabulary, this might be shorter. In addition, sentence length depends on the ideas you're communicating and the context they're given in. Strong ideas are often short, simple sentences, while connections and relationships may be a longer compound or complex sentences. Don't know how to connect compound and complex sentences? Read Cohesion (Part 2).

Ultimately, you want a mix of short, medium, and long sentences in English. 

So what's a clause?

It's a subject plus a predicate. Below are some clause examples separated into subject and predicate. Can you guess what type of word/s you can use as a subject or predicate? 

What's a subject?

It's what a clause is about. In other words, it is the person or thing the predicate refers to. For example, in our first example clause above, people is what are usually friendly is referring to.

In other types of languages, there isn't always a subject. There might be a more general 'topic' rather than an individual thing that gets focused on. However, in English, each clause usually has its own subject.

What's a predicate?

This is where it gets tricky and people have different opinions. What did you think? Some say that it's everything in the clause other than the subject. In other words, it's the verb phrase and anything else that goes with the verb. However, some modern grammar theories consider the predicate to be more important than the traditional 'subject' of a clause because the verb is the action or idea that other parts of the sentence depend on. This means that some people look at the predicate as the most important part of a sentence, and what was traditionally called the subject as less powerful than the verb. For your purposes, just check two things:

  • you have one subject and one main verb for each clause you write
  • any verbs before or after your main verb are verb-ing or infinitive (or have no tense)

This second point is important because we can only have one main verb phrase in a clause in English. Why? Because each clause only has one subject and predicate, and a predicate must contain a verb which agrees with the subject. Other verbs in the clause aren't allowed to do this, or it wouldn't be a clear English sentence! 

See the options for each part of a clause below. Do you use these different parts in your sentences?

What should I put in the subject position?

In English clauses, the 'subject' is very important and is usually what people focus on. Why? Because English is a 'subject-dominant' language, so people will choose what they want to focus on and move it to the front of the sentence. 

This is also why we usually have the subject first then a verb after, while other languages like your language might have a verb first, or not always require a subject. For instance, languages like Chinese, Arabic, Korean, Japanese, Turkish, Spanish, and Brazilian Portuguese are 'topic-prominent' or 'null-subject' languages, which means that there doesn't have to be a subject in every clause. 

Interestingly, people using those languages often don't distinguish between subject and object, so choosing whether to use active or passive voice in English might feel strange. However, because the subject has more focus in English, it really matters what you put in that position. So, think carefully about what you want to place there in your English sentences. 

Look at the examples below. See how you can say similar things in different ways by changing what's in the subject position. Are you using all of these structures in your clauses?

Where can I practise more?

For extra practice, try this site from the RMIT Study and Learning Centre or a grammar book or app (like the one below), and bring some sentences in to show a Study Support Teacher if you're an REW student. Remember that you can borrow a book from your local library if you'd prefer not to buy one. There are also grammar software programs like Tense Buster (use your RMIT login to access). 

Thanks for stopping by! Let us know in the comments what you liked or if you have any questions. 


aboriginal flag
torres strait flag

Acknowledgement of Country

RMIT University acknowledges the people of the Woi wurrung and Boon wurrung language groups of the eastern Kulin Nation on whose unceded lands we conduct the business of the University. RMIT University respectfully acknowledges their Ancestors and Elders, past and present. RMIT also acknowledges the Traditional Custodians and their Ancestors of the lands and waters across Australia where we conduct our business - Artwork 'Luwaytini' by Mark Cleaver, Palawa.