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.




Hi, I have been teaching English for some time; however, I still want to expand my knowledge of the language especially regarding the differences of American English and British English. Just recently, I saw this sentence listed as an example of a compound sentence: "She opened the gate but did not shut it." Is it acceptable? I tried checking other resources, but I am hoping you can give me a straight answer.

In addition, I noticed that you have listed "then" as a coordinating conjunction. Could you please share the explanation?
Thank you very much.

In the text books, the compound sentence should be two independent clauses. However, this sentence can be divided to "She opened the gate" and "did not shut it". The second clause is not an independent clause. Is there an explanation for this? Thanks.

Hello Lainie,

If you take a look at my comment just below this one you'll see that the second clause is formed with ellipsis. Certain words are omitted for stylistic (rather than grammatical) reasons - in this case, to avoid repetition - and a pronoun is used for the same reason. If we write the sentence out in full without these stylistic changes then we can see that we have two full independent clauses:

She opened the gate but she did not shut the gate.


Best wishes,


The LearnEnglish Team

Hi Laine,

The sentence you quote is perfectly fine. I'm not sure why you would think it not acceptable - perhaps you could explain what possible problems you see and we'll try to help you. There is some avoidance of repetition (ellipsis and the use of a pronoun) in the sentence:

She opened the gate but she did not shut the gate.

She opened the gate but did not shut it


'Then' can be used as a coordinating conjunction in my view, though this is not an entirely uncontroversial opinion. I think you might find the following discussion helpful:


Best wishes,


The LearnEnglish Team

Dear Sirs,
I have a question regarding parallel structures.It was explained in a creditable grammar book that the sentence below is a correct parallel structure :

''Inflation has three causes: excessive government spending, unrestrained
consumer borrowing, and an increase in the supply of paper money.''

because they are all adjective+ noun phrases ; however , I cannot figure out the adjective in the third one and I think it is wrong and should be written like this:

......., and increased supply of paper money .
Am I right ? Please help me out here.

Yours faithfuly,
Arvin Taj

Hello Arvin Taj,

You're right that the third item is not an adjective + noun phrase. The noun phrase beginning with 'an increase' has no adjective. 

Your alternative wording is grammatically correct (though it needs the indefinite article 'an'), but the original wording sounds more natural -- personally, I'd leave it like that and change the explanation of it.

All the best,
The LearnEnglish Team

Hi Kirk,

So, we can simply say they are all noun phrases. is that right?


Hello again Arvin,

Yes, they are all noun phrases

All the best,
The LearnEnglish Team

Another question sir about structure:
"If we were to eliminate the second 'I' from that example, the second clause would lack subject, making it not a clause at all."
(please disregard the thought of this sentence, as I took this sentence from another english learning site)
Sir my question is about the last phrase "making it not a clause at all".
What kind of clause is that? Im confused whenever i see that kind of clause preceded by a comma, and it doesn't start with a conjuction but with a verb(making).

Hello! Im confused about using/when to use commas in compound sentences. Do you have a post/lesson that will clearly demostrate how to use commas in a sentence? I searched for it in some sites, but i found it conflicting to others. Thanks a lot and I will appreciate your response.