Southwest Airlines Professional Communications Certification Practice Exam

What punctuation mark is used to separate a nonessential clause in a sentence?

1. Colon

2. Semicolon

3. Comma

4. Dash

The correct answer is: Comma

The punctuation mark that is used to separate a nonessential clause in a sentence is the comma. Nonessential clauses provide additional information that is not crucial to the main point of the sentence. Therefore, they can be removed without altering the overall meaning. Commas are employed to indicate a slight pause and to clarify that the clause is supplementary, making it clear to the reader that the surrounding content stands independently. While both dashes and semicolons can denote relationships between thoughts or clauses, they are used in different contexts. Dashes typically emphasize or set off information more dramatically, while semicolons connect closely related independent clauses. Colons serve to introduce lists, explanations, or quotations and are not suitable for separating nonessential clauses. The use of commas in this scenario creates a smoother reading experience and maintains the flow of the sentence, reinforcing the understanding that the information in the nonessential clause is additional rather than critical.