综掘机哪些情况不能开机。

－What do you think we can do for our aged parents?

－You_______ do anything except to be with them and be yourself. [ ]

A. don't have to

B. oughtn't to

C. mustn't

D. can't

Your plan sounds good.But we are short________money to carry it out.[ ]

A. for  

B. of

C. with  

D. in

进行普通混凝土立方体抗压强度测定时，其受压面应垂直于成型抹平面。 ( )

正在空中匀速上升的气球，它的势能将_________，动能将_________。（选填：“变大”、“变小”或“不变”）

泵房司机应做到（）的内容是知设备结构、知设备性能和工作原理、知设备技术特征。

A.三会

B.三知

C.三知道