对薄膜的管理重点搞好（）各项工作。
A.防风
B.防晒
C.防漏
D.防冻
E.防雹
参考答案：A, B, C, D, E
珠光体的平均碳的质量分数为6.69%。( )
完成下列反意疑问句.
1. He isn't a student, __________?
2. He likes basketball, __________?
3. They'll go to Shiqi tomorrow, __________?
4. Your mother can't swim , __________?
5. Tom has had his supper, __________?
