巷道断面中岩层面积（含夹石层）大于1/5小于（）的巷道界定为半

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问题单项选择题

巷道断面中岩层面积（含夹石层）大于1/5小于（）的巷道界定为半煤岩巷道。

A.3/5

B.4/5

C.1/5

D.2/5

答案

参考答案：B

连线题

将句子和相应的时间连线。
1. Many years ago 2. Now	A. there weren't any televisions.
	B. shecooked on the fire.
	C. we have got lots of food.
	D. we didn't have a TV.
	E. there are lots of buses and cars.

判断题

SS7型电力机车上电机励磁绕组由串励、他励组成，由于串励绕组电流小，可简化机车磁场消弱电路和牵引、再生制动转换的控制。