smg10e_handbook6

P1-b Place a comma after an introductory word, phrase, or clause.

Printed Page H-51

Sentences often begin with words, phrases, or clauses that precede the independent clause and modify an element within it. The comma following each introductory element lets the reader know where the modifying word or phrase ends and the main clause begins.

Naturally, this result didn’t help him any.
With a jerk, I lofted the lure in a desperate attempt to catch a fish and please my dad.
When we entered the honeymoon suite, the room smelled of burnt plastic and was the color of Pepto-Bismol.

If an introductory phrase or clause is brief—four words or fewer—the comma may be omitted unless it is needed to prevent misreading.

Without hesitation I dived into the lake.