Simple sentences:

A simple sentence has only one clause:

The children were laughing.
John wanted a new bicycle.
All the girls are learning English.

Compound sentences:

A compound sentence has two or more clauses:

(We stayed behind) and (finished the job)
(We stayed behind) and (finished the job), then (we went home)

The clauses in a compound sentence are joined by co-ordinating conjunctions:

John shouted and everybody waved.
We looked everywhere but we couldn’t find him.
They are coming by car so they should be here soon.

The common coordinating conjunctions are:

and – but – or – nor – so – then – yet

Complex sentences:

A complex sentence has a main clause and one or more adverbial clauses. Adverbial clauses usually come after the main clause:

Her father died when she was very young
Her father died (main clause)
when (subordinating conjunction)
she was very young (adverbial clause)

She had a difficult childhood because her father died when she was very young.
She had a difficult childhood (main clause)
because (subordinating conjunction)
her father died (adverbial clause)
when (subordinating conjunction)
she was very young (adverbial clause).

Some subordinate clauses can come in front of the main clause:

Although a few snakes are dangerous most of them are quite harmless
Although (subordinating conjunction)
some snakes are dangerous (adverbial clause)
most of them are harmless (main clause).

A sentence can contain both subordinate and coordinate clauses:

Although she has always lived in France, she speaks fluent English because her mother was American and her father was Nigerian
Although (subordinating conjunction)
she has always lived in France (adverbial clause),
she speaks fluent English (main clause)
because (subordinating conjunction)
her mother was American (adverbial clause)
and (coordinating conjunction)
her father was Nigerian (adverbial clause).

There are seven types of adverbial clauses:


  Common conjunctions
Contrast clauses  although; though; even though; while;
Reason clauses because; since; as
Place clauses where; wherever; everywhere
Purpose clauses so that; so; because + want
Result clauses so that; so … that; such … that
Time clauses when; before; after; since; while; as; as soon as; by the time; until
Conditional clauses  if; unless; provided (that); as long as

Complete the sentences with conjunctions.

Match conjunctions to functions.




Hello CareBears07,

Yes, that sentence is fine. It describes the only (in the speaker's view) two possibilities.


Best wishes,


The LearnEnglish Team

Hi Peter, thanks for your prompt reply in clearing my doubts. In terms of parallel construction, whereby some writers are particularly obsessive about, do you think it's better to rephrase the either-or clause so that both "sides" carry the same grammatical structure?

Hello CareBears,

Unless a non-parallel structure causes confusion, I'd say that's mostly a matter of personal style or of the kind of text you're writing.

All the best,
The LearnEnglish Team

Thank you, Kirk!!! I love this site at first sight!!! lol :)

Hi Team :

can we reduce the the compound sentence if it has the same subject ?
for example :
My hair is tangled & It needs to comb
reduce to
My hair is tangled & needing to comb

2- What is the maximum length of the compound-complex sentence? I mean
How many of clause I can put in sentence ?
Thanks for helping

Hello nkmg,

Yes, you can omit the second subject since it is clear from context what the subject of the verb is. But you need to change the wording a little bit – you could say either 'My hair is tangled and needs to be combed' (using a passive infinitive) or 'My hair is tangled and needs combing'.

As far as I know, there is no rule on the length of such a sentence. It's usually a question of how intelligible (or not) the sentence is, or a matter of style. Compared to many languages, sentences in English tend to be relatively shorter. It's not an easy solution for you, but as you read in English, look out for sentences such as these and take note of how they are constructed.

All the best,
The LearnEnglish Team

Hello Kirk :
Thank for helping. But I didn't understand Why we should use passive infinitive ? and

in another choice ( My hair is tangled and needs combing') why can we use gerund without passive ?

Hello nkmg,

You're welcome! An active verb can be used (e.g. 'I combed her hair') or a passive verb can be used ('Her hair was combed'), but here since the sentence doesn't say who combs the hair, a passive form is needed.

When the -ing form of a verb is used after 'need', it has a passive meaning -- this is just a structure that has developed in English over the centuries. If you'd like to learn more about, check out this BBC page.

All the best,
The LearnEnglish Team



What's the difference between an adverbial clause and adverbial phrase?


Hello Frank,

'Adverbial' simply tells us that the structure functions as an adverb. You can read about adverbials on this page.

A phrase is a group of words which forms on conceptual unit. For example, 'house' is a noun. 'The house' is a phrase, as is 'the big house', 'the big red house' 'the big red house with the blue door' and so on.

Clauses are generally larger units (though phrases can be quite long, as above) and are made up of phrases. Traditionally all clauses have at least a subject (a noun phrase) and a predicate (containing a verb), but most contain more than this and have one or more adverbial phrases.



Best wishes,


The LearnEnglish Team