吸入麻醉药可以增强肌肉松弛药的时效和强度，作用最强的是（）
A.异氟醚
B.安氟醚
C.氟烷
D.七氟烷
E.氧化亚氮
参考答案：A
Underground railway is being built in Shenyang. We are sure to take the subway to ______ in the city in no time.[ ]
A. get through
B. get around
C. get together
D. get over
直流发电机的空载损耗主要与（）有关。
A.电枢电流的大小
B.励磁电流的大小
C.电枢转速的高低
