Question

Which sentence does not contain any errors in comma usage? A. You know, of course, that she used to dive for her college swim team. B. Nobody ever bothered, it seems to tell me that. C. Believe it, or not Mom is going to dive from the high board. D. I never thought she'd do it to tell the truth.

Answer 1

It's A because that adverbial is normally followed by a comma.

Answer 2

"A. You know, of course, that she used to dive for her college swim team." does not have any errors in comma usage. "Of course" is almost always surrounded by commas.