空心活动配水管柱目前最多能配注()层。
A、二
B、三
C、四
D、五
参考答案:C
对岩石钻孔作业难度和定额影响较大的矿物成分是()。
A.云母
B.长石
C.石英
D.方解石
—How about going hiking this weekend?
—Sorry. I prefer ________ rather than ________.
A.to stay at home;go out
B.to go out;stay at home
C.staying at home;go out
D.going out;stay at home