采用二次升温法养护预应力混凝土构件，其目的是( )。
A．提高混凝土强度 B．消除初始塑性变形C．减少预应力损失 D．减小混凝土徐变
参考答案：C
There's no light on in the dormitory. They must have gone to attend the concert to be held on the
campus, ________?[ ]
A. didn't they
B. mustn't they
C. haven't they
D. shouldn't they
初下雨时，谨防路滑，最滑的应是（）路面。
A.水泥
B.泥土
C.砂石
D.渣油
