Learn English – Comma in compound/complex sentences

commaspunctuationsentence

Is there a rule, which states that one must or must not use comma before "then" in a sentence like this:

If you can read this, then you might want to answer this question.

Best Answer

Use comma in that sentence.

This is the general recommendation for sentences with a dependent clause followed by an independent clause. In your sentence:

  • Dependent clause: If you can read this

  • Independent clause: [then] you might want to answer this question.

From the Wikipedia page on Commas:

In English, a comma is generally used to separate a dependent clause from the independent clause if the dependent clause comes first: After I brushed the cat, I lint-rollered my clothes. (Compare I lint-rollered my clothes after I brushed the cat.)

Note that it doesn't mean that it is wrong to not use comma in this case. As noted by the same page:

While many style guides call for commas, many authors omit them, particularly with short sentences.