除氧器水位低对给泵有何影响？
参考答案：
引起给泵汽蚀。
----Tomorrow is a holiday. Why are you doing your homework?
-----I am doing these exercises now so that I won’t have _____ on Sunday.
A．it
B．them
C．for
D．to
肝性脑病发生的诱因有（）
A.上消化道出血
B.高蛋白饮食
C.合并严重感染
D.大量排钾利尿
E.使用镇静剂
