Answer:
While running down the street, John dropped his ice cream in the mud.
While looking through the library, I found several books on horses.
After flipping through the telephone directory, he found the name he wanted.
While eating breakfast one morning, he came upon an idea.
He noticed Tom's shoes were untied while he was picking up his pencil.
Explanation:
A dangling participial phrase occurs when it's not clear who is doing the action. Often that is because the independent clause is written in passive voice. By adding "while" or "after" and changing the independent clauses to active voice, the dangling participial is fixed. There is a clear subject that is actually described by the participial phrase.