离子交换树脂的化学性质取决于其所带交换基团的性质，如（）。
A.溶解性
B.溶胀性
C.选择性
参考答案：C
消防水泵吸水管、出水管上的控制阀应锁定在()位置，并有明显标记。
A.常开
B.常闭
C.半开
D.封闭
_____with his slippers on when he heard the terrible noise.[ ]
A. Out did the policeman rush
B. Rushed the policeman out
C. Out rushed the policeman
D. Out the policeman rushed
