轮胎侧面有磨损标记“▲”的，标记处的沟槽不足（）时，应立即更换轮胎。
A.1mm
B.1.6mm
C.2mm
参考答案：B
—Hi, Tom. Is your brother as active as you?
—No, he's a quiet boy. He is _________.[ ]
A. less outgoing than me
B. not so calm as I
C. more active than I
D. as outgoing as I
移刮板输送机机头和机尾时必须距采煤机后滚筒（）的距离，进刀后，刮板输送机机头、机尾必须一次移够步距。
A、25米
B、20米
C、15米
D、10米
