电流比校核，电流发生器一次输出电流应（）被试设备额定电流的5%，其波形应为正弦波。

A.不低于

B.不高于

C.低于

D.高于

The well-known Garub Site, unearthed in 1997, shows that man had made living there as early as 5,000 years ago.

A. human had lived


B. humans had lived
C. human being lived


D. human beings lived