SAT English Practice Question

The most common punctuation error that occurs in this type of writing is a comma splice. A comma splice is a comma used incorrectly to separate two complete sentences without a conjunction. This is incorrect because a comma cannot be used in this way to join two complete sentences. What is the main reason why this is a punctuation error?

1. A.it creates a run-on sentence.
2. B.it results in a phrase that’s too long.
3. C.it makes the writing too formal.
4. D.it makes the writing too casual.