Which set of sentences demonstrates proper semicolon usage to join two closely related independent clauses?

• A. The wind died down; night grew quiet.
• B. The wind died down; and the night grew quiet.
• C. The wind died down, the night grew quiet.
• D. The wind died down; therefore, the night grew quiet.

Answer: (D)

The main idea here is how a semicolon can connect two independent thoughts that are closely related. A semicolon can link two complete sentences directly, or it can set up a relationship with a transitional word like therefore, which is a conjunctive adverb.

In the correct choice, the semicolon sits between two independent clauses, and therefore acts as the bridge that signals a cause-and-effect relationship: once the wind died down, the night grew quiet. The word therefore functions as that bridge word, so you place the semicolon before it and a comma after it to show the connection clearly.

This is better than the other options for a couple of reasons. One option has a second clause starting with a lowercase word after the semicolon, which isn’t standard for beginning a new independent clause. Another option tries to sew the clauses together with a semicolon plus the coordinating conjunction and, which isn’t how semicolons are used with conjunctions. The last option uses just a comma to join two independent clauses, creating a comma splice.

So, using a semicolon before a conjunctive adverb like therefore and then a comma after it demonstrates the proper way to connect two closely related independent clauses with clear, correct punctuation.