安全工器具应保持(),轻拿轻放,防止意外损坏。
A、清洁、干燥,摆放整齐;
B、外观完整;
C、试验合格
参考答案:A
There was a lot of people standing at the door and the small girl couldn't get . [ ]
A between
B. through
C. across
D. beyond
渣口破损的主要原因是指()。
A.小套水压过低
B.渣中带铁
C.受机械撞击