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.

• I like coffee. Mary likes tea. → I like coffee, and Mary likes tea.
• Mary went to work. John went to the party. I went home. → Mary went to work, but John went to the party, and I went home.
• Our car broke down. We came last. → Our car broke down; we came last.

Making compound sentences with coordinating conjunctions

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

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).

and

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

• We use and to join two clauses that have equal value, for example: London is in England, and Rome is in Italy.
• We use and to join two clauses when the second clause happens after the first clause, for example: There was a big bang and the lights went out.
• We use and to join two clauses when the second clause is a result of the first clause, for example: He went to bed early, and the next day he felt better.

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.

Making compound sentences with semicolons

Occasionally, we join independent clauses with a semicolon (;).

• He studied very little; he failed his exams.
• The sky is cloudy; it's going to rain.
• Ram cut the grass; Ati trimmed the hedge; Tara watched.

Making compound sentences with conjunctive adverbs

We can also join independent clause with words and phrases like moreover, however, at least (conjunctive adverbs). In this case, the conjunctive adverb must be preceded by a semicolon (;) and followed by a comma (,).

Look at these examples:

• John loves Mary; however, Mary doesn't love John.
• Salad is not expensive; moreover, it's very healthy.
• What he did was incredible; in fact, I could hardly believe it.

The table shows all seven coordinating conjunctions, and a few conjunctive adverbs as examples.