等外水准测量同一标尺黑红面读数差不应超过（）mm。
A.3
B.4
C.5
参考答案：B
His idea is always so advanced that we all think that he is____ our time.
A．before
B．in the front of
C．ahead of
D．beyond
水泵或浆泵启动后应作哪些检查？
