2. Compound Sentences

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Compound Sentences

Two independent clauses (two simple sentences) joined by a coordinator is known as a compound sentence. The seven coordinators are for, and, nor, but, or, yet, so.  If you take the first letters of each coordinator, they spell FANBOYS. This makes it easier to remember.

Independent Clause, + coordinating conjunction + Independent Clause = Compound Sentence


To better understand compound sentences, look at the examples below.

  1. The company built a new factory, so they are hiring new employees.
  2. Some students study better in the morning, and other students study better in the evening.
  3. Students often go to a gym to get exercise, but it is better to get exercise in the open air.
  4. We live in a globalized world, yet there is still much fighting.

Coordinating Conjunctions (FANBOYS)

If you combine two simple sentences together with a comma and a coordinating conjunction, you have a compound sentence. Here are the seven coordinators with examples:

F – for

  • He felt bad, for he knew he had made a mistake.
  • She turned on the radio, for she knew it was time for her program.

NOTE: for means because or since

A – and

  • He was hunger, and he was tired.
  • She bought a new shirt, and she bought a new sweater.
  • Some people prefer the city, and some people prefer the country.

N – nor

  • She doesn’t have a computer, nor does she have an iphone.
  • I cannot sing, nor can I play the piano.
  • He did not come to class yesterday, nor did he do his homework.
  • The company did not advertise last month, nor did they make a profit.

NOTEnor means both sentences are untrue.  It is important to note the sentence pattern in the second clause. Look at the following sentence.

The factory did not comply with government regulations, NOR did they change their safety policy.

The meaning is the factory should have done both of these, but they failed to do either.  It is important to note the word order on the second clause.  In the first clause, you have a subject (The Factory), a helping verb (did not), and the verb (comply).  In the second clause, you have the helping verb (did), then the subject (they), and the verb (change).

B – but

  • They worked hard, but they did not get paid.
  • He took a lot of food on his trip, but he did not have enough.
  • She wanted to buy a new computer, but she did not have enough money.

O – or

  • You can go to New York by train, or you can go by plane.
  • Students can take Physics 201, or they can take Biology 201.
  • You can come with me, or you can go with her.

Y – yet

  • They worked hard, yet they did not get paid.
  • He looked at the new car, yet he did not have any money.

NOTEyet means almost the same as but.

S – so

  • They need to learn English, so they study online.
  • She has a test tomorrow, so she is studying in the library.
  • He doesn’t have any money, so he needs to work.

Run-on Sentences

Another error that students often make is putting two sentences together. We call these run-on sentences. A run-on sentence is two independent clauses put together without the correct punctuation.

How would you correct the following run-on sentence?

 I studied biology in college it was difficult for me.

There are two ways you can correct this run-on.

First, you can make two sentences: I studied biology in college. It was difficult for me.

Or you can join them together with the conjunction and:  I studied biology in college, and it was difficult for me.

Let’s look at one more run-on sentence.

Public safety should be our first concern more research is needed before GMOs are sold on the market.

The sentence is difficult to read. There are two ideas competing in one sentence. You can correct the error by making two sentences, or by making a complex sentence.

To make two sentences, simply put a period after concern, and now you have two sentences.

Public safety should be our first concern. More research is needed before GMOs are sold on the market.

Or you can make a complex sentence by adding because at the beginning and a comma after concern.

Because public safety should be our first concern, more research is needed before GMOs are sold on the market.

Comma Splice

A comma splice is when two simple sentence are joined together with only a comma and no conjunction. For example:

The store carries bread, they don’t carry tomato sauce.

This sentence is missing the conjunction. To correct it, one of the FANBOYS needs to be added. Such as, The store carries bread, BUT they don’t carry tomato sauce.

Two independent clauses can also be joined using a semicolon (;). The store carries bread; they don’t carry tomato sauce.

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