Proofreading and Editing Precision Practice Exam

Punctuation with dependent clauses depends on where the dependent part appears. A clause like because it was happy cannot stand alone and must attach to a main clause. If the dependent clause comes after the main idea, you don’t need a comma. If it comes before the main idea, you usually put a comma after the introductory dependent clause.

In the correct sentence, the main clause comes first: The dog wagged, and the reason follows with because it was happy. Because the dependent clause explains why, but comes after the main idea, no comma is needed between the main clause and the dependent clause, so the sentence is clean and correctly punctuated.

The other options miss the stated pattern or punctuation rule. One option includes a comma before and in a single subject with two verbs, which isn’t about a dependent clause at all. Another option places the dependent clause at the start but leaves out the comma after it, which is normally required. The remaining option lacks the dependent clause entirely and simply shows a simple sentence with two verbs, which doesn’t match the test’s focus on dependent clauses.