Hi! I’m Kathy Ide. In addition to being a published author, I’m a full-time professional freelance editor. For CAN, I’m blogging about tips for writers based on the manuscripts I edit.
A dependent clause that is restrictive (that is, it cannot be omitted without changing the meaning of the sentence) should be followed by a comma when it comes before a main clause. Example:
After she read Rene Gutteridge’s book, Linda felt motivated to write a novel too.
A restrictive dependent clause should not be preceded by a comma if it follows a main clause. Example:
Linda felt motivated to write a novel after she read Rene Gutteridge’s book.
If the dependent clause is nonrestrictive (provides supplementary or parenthetical information not essential to the meaning of the sentence), it should be preceded by a comma.
I’d like to borrow that book, if you don’t mind.
At last she arrived at the banquet, when the food was cold.