调压回路使系统整体或某一部分的压力()。当把调压回路中的溢流阀换为比例溢流阀时,这种调压回路成为()。
参考答案:保持恒定数值;比例调压回路
Li Yundi, took part in the 14th Chopin International Piano Competition in _______ and won
first prize in his group. [ ]
A. Germany
B. Austria
C. Poland
D. France
具有清肝明目,润肠通便作用的药物是
A.地龙
B.羚羊角
C.决明子
D.钩藤
E.天麻