—Can you swim in a river? —_______.
| A．Great! | B．Of course. |
| C．Good idea. | D．What about you? |
---- It’s very important for everyone to exercise. do you exercise?
----Three or four times a week.
| A．How long | B．How far |
| C．How soon | D．How often |
---- 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 |