The young mother kept ______ the house with three children in it , because she wanted to keep it ______.
| A．cleaning; clean | B．cleaning; cleaning | C．clean; clean | D．clean; cleaning |
---- Is that girl Susan?
---- It ______ be her. She left for Beijing yesterday.
| A．needn't | B．can't |
| C．mustn't | D．couldn’t |
----Shall we go to the amusement park this Sunday, mum?
---- Sure, ________ I am busy.
| A．unless | B．if |
| C．but | D．or |
This is the third time the famous scientist __________ the United States.
| A．has been to | B．has been in |
| C．has come to | D．has gone |
----Philip has gone to New Zealand．
----Oh，can you tell me________?
| A．when did he leave | B．when he is leaving |
| C．when he left | D．when is he leaving |
No one can achieve success __________ effort.
| A．beyond | B．with |
| C．without | D．beside |