641] Please ______ that you have closed all the windows and turned off the lights before you leave the room.

[译文] 在你离开房间之前请查一下你是否把所有的窗子和灯都关上了。

　 A. make sure 　 B. be sure

　 C. bring out 　 D. hold up

[答案及简析] A。 be sure 有把握，确信；make sure 务必，一定，千万。

640] When he was sixty years old, he _____ his hometown.

[译文] 当他60岁的时候，他就回到了他的故乡。

　 A. returned 　 B. returned back

　 C. returned to 　 D. went back

[答案及简析] C。 return 归来，回来，不再和副词back连用。

639] ______ you understand the rule, you can do it well.

[译文] 你一旦理解了规则，你就会把它做好。

　 A. For 　 B. As

　 C. Once 　 D. While

[答案及简析] C。 once连词，引导状语从句，"一旦"。

638] The room ____ voices of the children.

[译文] 房间里充满了孩子们的声音。

　 A. filled with 　 B. was filled with

　 C. full of 　 D. was full with

[答案及简析] B。 be filled with "充满"。

637] I can hardly heat the radio. Would you please ______?

[译文] 我几乎听不到收音机了。请把他开大一点好吗？

　 A. turn it on 　 B. turn it down

　 C. turn it up 　 D. turn it off

[答案及简析] C。 turn up 开大一些；turn off关掉； turn on 打开；turn down关小一些。

636] They made an important decision ______ the end of the meeting.

[译文] 在会议结尾时他们做了一个重要的决定。

　 A. in 　 B. by

　 C. on 　 D. at

[答案及简析] D。 at the end of 固定搭配"在…结尾"，"在…底／末"。

635] The boy was not allowed ______ his brother’s bike.

[译文] 不容许这个小孩用他哥哥的自行车。

　 A. to use 　 B. using

　 C. use 　 D. used

[答案及简析] A。 考查动词的用法be allowed to do sth.被容许做什么。

634] He _____ tasted the mixture and give a smile.

[译文] 他很高兴地尝了尝混合物然后笑了笑。

　 A. glad 　 B. gladly

　 C. was glad 　 D. was glad to be

[答案及简析] B。 副词才能修饰动词。

633] None of the students watched the teacher______.

[译文] 没有一个学生在认真听老师讲课。

　 A. careful enough 　 B. enough carefully

　 C. carefully enough 　 D. enough careful

[答案及简析] C。 enough作为副词，在修饰副词，形容词时要后置。

632] Miss Yang will teach us Chinese today ____ Mr Zhang.

[译文] 今天杨老师代替张老师给我们上语文课。

　 A. instead 　 B. instead of

　 C. to 　 D. of

[答案及简析] B。 instead 是副词；instead of是介词短语，才能跟宾语。