机柜间链式接地线的截面积不应小于（）mm2。
A.4
B.6
C.10
参考答案：B
Most museums are just for looking. But today some of them have things for you to touch. The signs say, "________!"
A．Be touching
B．To touch
C．Do touch
D．No touch
等面叶的主要代表物种有哪些？
