22 Commas and Compound Sentences
KEY CONCEPTS
A compound sentence often combines two separate sentences by using a comma with the conjunctions and, but or or.
EXAMPLE 1
Simple sentence – The game started an hour late. (simple sentence)
Simple sentence – The delay did not affect the fans’ enthusiasm. (simple sentence)
Compound sentence – The game started an hour late, but the delay did not affect the fans’ enthusiasm. (Note the placement of the comma.)
EXAMPLE 2
Simple sentence – The commission will release a summary of next year’s budget during a press conference Tuesday. (simple sentence)
Simple sentence – The mayor will delay the press conference to make revisions. (simple sentence)
Compound sentence – The commission will release a summary of next year’s budget during a press conference Tuesday, or the mayor will delay the press conference to make revisions. (Note the placement of the comma.)
No comma is needed when two verbs share a single subject. The following sentence is an example of a compound verb, but not a compound sentence, so no comma is used.
The batter rounded third base and sprinted home.
In this case, the two verbs (rounded and sprinted) share the same subject (batter), so no comma is needed.
Guidelines for comma usage are not as consistent as guidelines for apostrophes or subject-verb agreement. Most media writers, however, follow this chapter’s advice about comma usage in constructions that combine two sentences into one.
First, we need to learn or review some terminology. Sometimes we want to merge two sentences into one, usually with a comma and a conjunction such as and, but or or. We call this construction a compound sentence.
In a compound sentence, each half of the construction has its own subject and accompanying verb. Based on that description, try the following flip card.
Next, answer this true-false question.
In the true/false question above, you don’t need a comma before the conjunction but. No comma is necessary when you are just connecting two verbs with the same subject. This type of construction creates a compound verb, not a compound sentence.
Here’s an additional example:
The general briefed reporters and distributed pamphlets.
One subject (general) with a compound verb (briefed and distributed) = No comma needed.
Conversely, a comma is needed before the conjunction and in the following example of a compound sentence:
The general briefed the reporters, and his aides distributed pamphlets.
The compound sentence above has two components:
The general briefed the reporters.
His aides distributed the pamphlets.
Because these components are two simple sentences that can stand alone, we combine them with a comma and the conjunction and.
The general briefed the reporters, and his aides distributed pamphlets.
The next flip-card question gives you three choices.
MORE PRACTICE FOR PROFICIENCY
Below are additional usage questions based on this chapter. These questions may help you study for course assignments or a proficiency exam.
If you want explanations for the practice exercise above, click on each sentence number.
WRITING EXERCISE
1. Write your own compound sentence that uses the conjunction or.
2. Write your own compound sentence that uses the conjunction but.
3. Write your own simple sentence that contains a single subject followed by a compound verb.
4. In two tightly constructed sentences, explain your key takeaway from this chapter. Do not use any first-person pronouns (such as I, me, my or mine) in your writing.
