Please remind your grandpa to take medicine on time, for a man of his age ____be very forgetful．

---Must I work out the problem right now?---Yes, you _______. It’s very serious. 

 ---Must I answer it in English?---No, you _______. You can use Chinese.

— Oh, my cat is really fat.— You __ have given her so much food.

— Who has done that again? — _______ you ask? Little Tom, of course!