制氢站所有防雷和防静电接地装置要定期检测，接地电阻（）年至少_爱下问搜题

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问题单项选择题

制氢站所有防雷和防静电接地装置要定期检测，接地电阻（）年至少检测一次。

A、一

B、二

C、三

答案

参考答案：A

选择题

It is believed that a new kind of drug _____ by the scientists and they are hopeful that they will succeed in a couple of months.

A. has been developed
B. is being developed
C. is developing
D. has developed

单项选择题

软件质量因素分为多个方面，软件的健壮性属于哪个方面的特性

A．产品运行

B．产品修改

C．产品转移

D．产品维护