空调水管支架安装中，在有较大位移的管段应该设置使用（）支架。
A、固定支架
B、滑动支架
C、滚柱支架
D、滚珠支架
参考答案：A
Not until they left school ____how much their teachers loved them and helped them.
A．that they realized
B．had they realized
C．when they would realize
D．did they realize
ZYJ7-J170/4000电液转辙机动作时间不大于（）。
A、3.8s
B、6s
C、7.5s
D、10.5s
