覆盖塑料薄膜养生,宽度应大于覆盖面()mm,两条薄膜对接时,搭接宽度不应小于()mm。
A、600;400
B、400;400
C、400;600
参考答案:A
He is ________ honest man and he has been waiting for over ______ hour.
A.a; a
B.an; a
C.a; an
D.an; an
操作隔离开关有哪些基本原则?