NOTE: An independent (or strong) clause is a simple sentence with a subject, verb, and a complete thought. A dependent (or weak) clause has a subject and verb but does not express a complete thought.
Rule – Use a comma to separate two independent clauses joined by a coordinating conjunction—and, or, but, for, nor. You may omit the comma if the clauses are both short.
Examples:
I have painted the entire house, but he is still working on sanding the doors.
I paint and he writes.
Rule – A comma splice is an error caused by joining two independent clauses with only a comma instead of separating the clauses with a conjunction, a semicolon, or a period. A run-on sentence, which is incorrect, is created by joining two strong clauses without any punctuation.
Examples:
Incorrect:
Time flies when we are having fun, we are always having fun. (Comma splice)
Time flies when we are having fun we are always having fun. (Run-on sentence)
Correct:
Time flies when we are having fun; we are always having fun.
OR
Time flies when we are having fun, and we are always having fun.
OR
Time flies when we are having fun. We are always having fun.
Pop Quiz
Choose the correct sentence.
1A. Morgan did all of the grocery shopping but all Ralph did was watch the game.
1B. Morgan did all of the grocery shopping, but all Ralph did was watch the game.
2A. Morgan shopped but Ralph watched the game.
2B. Morgan shopped, but Ralph watched the game.
3A. Alphonso’s home sits high on the hill, you can see Mt. Diablo from there.
3B. Alphonso’s home sits high on the hill you can see Mt. Diablo from there.
3C. Alphonso’s home sits high on the hill, and you can see Mt. Diablo from there.
3D. Alphonso’s home sits high on the hill; you can see Mt. Diablo from there.
4A. I don’t know whether we’ll get home tonight. We still have a long way to go.
4B. I don’t know whether we’ll get home tonight, for we still have a long way to go.
4C. I don’t know whether we’ll get home tonight we still have a long way to go.
Pop Quiz Answers
1B. Morgan did all of the grocery shopping, but all Ralph did was watch the game.
2A. Morgan shopped but Ralph watched the game. OR
2B. Morgan shopped, but Ralph watched the game.
(You may omit the comma if the clauses are both short.)
3C. Alphonso’s home sits high on the hill, and you can see Mt. Diablo from there. OR
3D. Alphonso’s home sits high on the hill; you can see Mt. Diablo from there.
(3A. is a comma splice. 3B. is a run-on sentence.)
4A. I don’t know whether we’ll get home tonight. We still have a long way to go. OR
4B. I don’t know whether we’ll get home tonight, for we still have a long way to go.
(4C. is a run-on sentence.)
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