When you use it
Use this rule to detect and correct sentences where an opening descriptive phrase does not logically modify the subject that immediately follows the comma.
Watch out
Do not leave an unrelated noun or object right after the comma. Either place the true performer of the introductory action directly after the comma, or turn the opening phrase into a complete clause with its own subject and verb.
Drafted from Grade 12 English, pages 74-102, then checked twice before it went up

