Compound Sentences

A compound sentence is like two or more simple sentences added together.

In fact, as we saw in sentence structure, a compound sentence is two (or more) independent clauses joined by a coordinating conjunction or a semicolon. A compound sentence does not contain any dependent clauses.

Making compound sentences with coordinating conjunctions

Usually, we join independent clauses with one of the 7 coordinating conjunctions.

independent clause independent clause

The term coordinating conjunction sounds complicated, but in fact there are only seven of them and they are all short, one-syllable words: for—and—nor—but—or—yet—so — remember them with the mnemonic FANBOYS.

The most common of these coordinating conjunctions are and, but and or, in that order. Note that a comma (,) must come before the coordinating conjunction except when the clauses are short (in which case the comma is optional).

independent clause independent clause

and

The and conjunction is the most common conjunction. It has several uses.

but

We use the but conjunction to introduce a clause that contrasts with the preceding clause, for example: Mary ran fast, but she couldn't catch John.

or

We use the or conjunction to join two alternative clauses, for example: Will Mary go, or will John go?

nor

We use the nor conjunction to join two alternative clauses when the first clause uses a negative such as neither or never. In this case both clauses are untrue or do not happen, for example: Mary never wrote the letter, nor did she call him. (Note the inversion of subject and auxiliary: did she.)

for

We use the for conjunction (meaning something like because) to join two clauses when the second clause is the reason for the first clause, for example: He felt cold, for it was snowing.

yet

The yet conjunction is similar to but. It means something like but at the same time; but nevertheless; but in spite of this. As with but, there is a contrast between the clauses, for example: I have known him for a long time, yet I have never understood him.

so

The so conjunction means something like therefore; and for this reason. We use so to join two clauses when the first clause is the reason for the second clause, for example: He was feeling sick, so he went to the doctor.