Both his parents look sad . Maybe they __what's happened to him .
| A．knew | B．have known |
| C．must know | D．will know |
— ______ do you go to the gym?
— Twice a week
| A．How often | B．How soon |
| C．How many | D．How long |
— Where is Jenny?
— She is doing her homework ______ the classroom.
| A．of | B．on | C．in | D．to |
Mike lost his key. ______ couldn’t enter the room.
| A．He | B．She | C．They | D．It |
I met Jerry in the hotel yesterday, but he didn’t tell me________.
| A．which floor did he live | B．which floor he lives on |
| C．which floor he lived on | D．which floor does he live |
We don’t believe he will come here on time, ________?
| A．will he | B．won’t he |
| C．does he | D．is he |