新修订的《北京市安全生产条例》将下列作业界定为危险作业:爆破、吊装、()建筑工程拆除、临近高压输电线路、在有限空间内作业
A.悬吊、挖掘
B.井下作业
C.水下作业
参考答案:A
—What do you think of this jacket?
—Well, I like its color, but the price is a little bit too ______. I don't think I can afford it. [ ]
A. cheap
B. low
C. expensive
D. high
一弹簧振子作简谐振动,总能量为E,如果简谐振动振幅增加为原来的两倍,则它的总能量变为()。
A.
B.
C.2E
D.4E