Read these sentences and complete them, using a verb + out. Use the suitable tenses.
1. You have to _______ the problem yourself. I can’t do it for you.
2. I thought the two books were the same until a friend of mine _______ the difference.
3. Sometimes it ______ cheaper to eat in a restaurant than to cook at home.
Raymond Murphy. English Grammar in Use- Cambridge: CUP, 379p.