安装衬板时出现环形（）接缝，否则筒体易受物料的磨损。
A.不应
B.应
C.可以
参考答案：A
变压器中的油起绝缘和（）作用
A.灭弧
B.冷却
C.防潮
It is _____ to make another effort and try to finish the work ahead of the time _____ for it to be finished. [ ]
A. worth; fixed
B. worthwhile; made
C. worthy; fitted
D. worthwhile; set
