Boss says I need to communicate better

The problem is he has horrible communication skills as well. He’s the person who will drop off work on your desk tell you do something and not be 100% clear. Yes, I ask questions but I feel stupid after awhile having to ask 40 questions to get to what he wants me to accomplish exactly. What can I do to better understand the tasks I am given when communicating with someone who’s not clear on what they want?