A compound sentence is two or more complete, simple sentences that are joined together by a conjunction.  Conjunctions are words like and, but, or, nor, so, for, yet. For a compound sentence to be punctuated correctly, there must be a comma before the conjunction. 

Use a comma before the conjunction (and, but, or, nor, so, for, yet)
that joins the two or more clauses (simple sentences) that
make up a compound sentence.

Remember: two simple sentences joined by a conjunction become a compound sentence.  Remember, the comma always comes before the conjunction.

 
Also remember: watch out for simple sentences that have one subject and two verbs.  These sentences do not require commas because they are not compound sentences!

 

Let's practice working with using commas in compound sentences!

 

Read each sentence below.  Decide whether or not it is a compound sentence and needs a comma or if it is a simple sentence containing a compound verb that is correct as it is, then check your answer.

  1. Andy plays baseball but his brother Joe prefers lacrosse.     

  2. Carlos bats and throws left handed.                                       

  3. Evan works out every day so he stays in top condition.

  4. Liz loves to go to the movies but her sister prefers to read.

  5. Anna wanted a part in the play but she missed the tryout.

  6. Rob works after school because he wants to buy his own car.

  7. Olivia collects and sells rare old books.

  8. Jay took a sailing course so he goes sailing whenever he can.

  9. I just read the book Seabiscuit and I thought it was interesting.

  10. Seabiscuit out ran and beat the greatest race horses of his time.

How did you do? 

When you are working with compound sentences, just remember two things:

  1. Whenever you have a compound sentence, two simple sentences joined together with a conjunction, a comma is needed before the conjunction.
     

  2. When you have a simple sentence with two verbs, no comma is needed.

 

Click on the Chalk board to return to the lesson on
commas in compound sentences!

 

 

There are many other important and useful comma rules that you should know to improve your communication when you write.  Follow the links below to the lessons that introduce them:

Commas in Dates, Addresses, & Letters

Commas
in a
Series
 

Commas with Interrupters
 


Commas in Direct Address
 

Commas With Adjectives
 

 

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