备用泵进出门应在()位置。
参考答案:开启
Have you finished the book___you borrowed from the library?
A. which B. it C. what
完全紊流状态下,矿井风阻特性曲线是一条()。
A.直线
B.二次抛物线
C.双曲线
D.指数曲线