— Are you going to Beijing by air?— It’s fast, but expensive. So I’m not sure. I _____ take a train. 

— Must I stay here with you?—No, you_____. You may go home, but you ______go to the net bar.

–Look at that girl! Is it Susan? --No, it _______ be her. She has gone back to her hometown.

— My dog is really fat.   — You______ have given it so much food. 

Harry is feeling uncomfortable. He _______too much at the party last night.