起动机制动试中如果制动转矩小、电流大，说明（）有匝间短路或搭铁故障。
A.磁场绕组或电枢绕组
B.磁场绕组
C.电枢绕组
D.主电路接触不良
参考答案：A
There were so many cars held up by the heavy rain on the road that we had no but to wait. [ ]
A. alternative
B. difference
C. relation
D. opposition
污水中的油粒采用气浮法分离，其有利条件是（）
A.θ＞90°
B.θ＜90°
C.密度小于1
D.粒径小
