除中
参考答案：久病之人，本不能食，突然欲食，甚至暴食，是脾胃之气将绝之象。
It is well known that knowledge is ____ treasure house, but practice is ___ key to it.
A．a; the
B．the; the
C．a; x
D．x; the
闸阀的（）是关键部件，它决定闸阀的工作性能、密封性能和使用寿命。
A、阀体
B、阀盖
C、阀杆
D、闸板
