千米钻孔钻孔上下探顶、底板轨迹图上可以读出煤层（）
A.厚度
B.走向
C.倾向
D.分布
参考答案：A
--Could you tell me ______________ for class this morning?
--I am sorry, Mrs. Lin. I got up so late that i couldn’t catch the first bus.
A．why were you late
B．why you are late
C．why are you late
D．why you were late
在主要运输巷道，轨枕的规格及数量应符合标准要求，间距偏差不得超过（）。
A、90mm
B、50mm
C、110mm
