Doctors advise us ________masks on such hazy days.
| A．wear | B．wearing |
| C．to wear | D．worn |
We got mad ______ the team for losing the match.
| A．at | B．in | C．on | D．about |
I got home _____ they were having dinner.
| A．as soon as | B．while | C．because | D．After |
---Could we buy a piano， Jack?
---I’m afraid there ______ enough room for one in the house.
| A．aren’t | B．are | C．isn’t | D．is |
--Could you please _____ in the room?
--Oh， I’m sorry.
| A．not smoking | B．not smoke |
| C．not to smoke | D．don’t smoke |
_____ have you been swimming? For five years.
| A．How many times | B．How long |
| C．How often | D．How much |