You shouldn't be angry with your teacher if he _____ you.             [ ]

A. is worried about      

B. is strict with            

C. laughs at

判断离心泵的正反转，下面说法正确的是（）。

A.反转时电流指示很低

B.反转时压力指示很低

C.泵轴朝着入口转是正转

D.泵轴朝着出口转是正转