Superbowl commercial (perfectly) target (their) demographics because the advertisers regularly (spent) exorbitant amounts of time and money (designing) the ads. (no error)
The answer is (spent) and i know its because of the tense, but how is (designing) correct here? isn’t it a misplaced modifier because ‘money’ cannot design???
No, designing is not a modifier. It’s part of the verb phrase “spend ___ designing.”
A similar sentence that is correct: I spent an hour yesterday watching television.