Commas After Introductory Words, Phrases, and Clauses
Thank you to Purdue Owl Online Writing Lab! http://owl.english.purdue.edu/owl/resource/607/03/
Words: The coaches reviewed the game strategy. Meanwhile, the athletes trained on the Nautilus equipment.
Phrases: Barking insistently, Smokey got us to throw his ball for him.
Clauses: Because he kept barking insistently, we threw the ball for Smokey.
Introductory clauses start with adverbs likeafter, although, as, because, before, if, since, though, until, when, etc.
When to use a comma
Introductory elements often require a comma, but not always. Use a comma in the following cases:
- After an introductory clause.
- After a long introductory prepositional phrase or more than one introductory prepositional phrase.
- After introductory verbal phrases, some appositive phrases, or absolute phrases.
- If there is a distinct pause.
- To avoid confusion.
When not to use a comma
Some introductory elements don't require a comma, and sometimes the subject of a sentence looks like an introductory element but isn't. Do not use a comma in the following cases:
- After a brief prepositional phrase. (Is it a single phrase of fewer than five words?)
- After a restrictive (essential) appositive phrase. (For more informations, see http://owl.english.purdue.edu/owl/resource/596/01/ appositives.)
- To separate the subject from the predicate.
