Answer: Jake was surprised to see a large boulder falling off the cliff.
Explanation: a misplaced modifier (also called a dangling modifier) is a group of words that is placed awkwardly in a sentence so that it appears to modify or refer to an unintended word. In the given sentence "Falling off the cliff, Jake was surprised to see a large boulder" the modifier "Falling off the cliff" because it isn't clear if it's Jake or the boulder that are falling, the revision that corrects this misplaced modifier is Jake was surprised to see a large boulder falling off the cliff.