在存放放射性元素时，若把放射性元素①置于大量水中；②密封于铅盒中；③与轻核元素结

同义句转换, 每空一词。  

1. She was first in the competition. 

    She ______ _______ _______ in the competition.

2. We couldn’t go there because the weather was bad. 

    We couldn’t go there _______ _______ the bad weather.

3. Sam started to learn how to swim at the age of three.

    Sam started to learn how to swim ______________ _______ three.

4. Mike is so young that he can’t go to school.

    Mike is _______ _______ _______ go to school.

5. People called him "a talented boy".

    He _______ ________ "a talented boy".  

设D是由y=x，y=0及所围成的第一象限区域，则二重积分等于（）。

A.πa²/8

B.πa²/4

C.3πa²/8

D.πa²/2

班级的软文化即反应一个班级的班风或制度建设情况。(　　)

西餐服务中，面包、黄油应在客人订食品订单（）提供。

A.之前

B.之后

C.当中

D.同时

以下可能造成复印图像全白的是( )

A．光导体失效

B．显影器未工作

C．未转

D．复印纸太潮

E．墨粉用完