Take another look at the sentence:
Swerving to miss a squirrel in the street, a fire hydrant crumpled the hood
of Harold's car.
Swerving to miss a squirrel in the street, a participle phrase, comes right before fire hydrant, an illogical target. The people behind the wheel, not fire hydrants rooted in the ground, can swerve to keep the squirrels safe! Before you continue, review the rules for misplaced and dangling modifiers.
Go back to the sentence to try again.