–Sorry, Professor Smith. I didn’t finish the assignment yesterday. --Oh, you _____ have done it as yesterday was the deadline. A. must B, mustn’t C, should D. shouldn’t
The audience __________ before TV sets are listening to Yi Zhongtian's stories with their eyes __________ upon him.
The boy insisted that he __________ the glass. He said that he was not there then.
—Sorry, sir. I'm late again. —What excuse will you __________ for yourself this time?
This box __________ all the books you need, __________ an English-Chinese dictionary.
We'd better set off or it will be dark __________ we know it.