- set off introductory words, phrases and clauses from the main part of a sentence.
- help save the reader’s time and reduce the chances of misinterpreting what you write.
The examples below show how introductory words, phrases and clauses are set off with commas.
· Disappointed, we left the party shortly after we arrived.
· Annoyed, John stomped back to his room and slammed the door.
· Expecting the worst, we stopped spending and started saving.
· Badly injured in the accident, the actor was absent for more than three months.
· If we plan carefully for our trip, we can see and do a lot of things.
· While we were having lunch, an important call came.
· Because we left before the seminar ended, we were not eligible for the free trip to Shanghai.
In the sentences above, the first part of each sentence, also known as the subordinate/dependent clause is followed by a comma. However, if you reverse the sentence parts, making the independent clause the first clause in the sentence, you would NOT need a comma.
- The actor was absent for more than three months after the he was badly injured in the accident.
- An important call came while we were having lunch.
- We were not eligible for the free trip to Shanghai because we left before the seminar ended.