You are at a grocery store and your fridge is empty. You say: "We _______ buy _______ groceries for the week."
need to / some
Your friend is offering you a ride, but you have your own car. You say: "Thanks, but I _______ drive myself to the party."
can
You are looking at a very expensive menu and checking your wallet. You say: "I _______ spend _______ money on dinner tonight."
can't / much