在农电生产系统中，故障记录填写时，不是必填项的是（）
A.故障性质
B.故障简题
C.故障相别
D.运行班组
参考答案：C
— Do you regret________ up your opinion that every child should take part in service learning?
— No.On the contrary, I think it is very necessary. [ ]
A. bringing
B. to bring
C. to be brought
D. being brought
最常使用的射线挡块材料是()
A、蜡
B、低熔点铅
C、锡
D、铜
E、铁
