常用的校核方法就是利用大功率笼型异步电动机的启动条件进行校核。由于在笼型异步电动机启动时,柴油发电机出线端将引起很大的电压降,按相关规范要求,此时柴油发电机配电屏母线上的电压不应低于额定电压的( )。
A. 60%
B. 70%
C. 80%
D. 90%
投入并联的各台发电机的最大功率与最小功率之比应不超过( )。
A. 2:1
B. 4:1
C. 3:1
D. 3:2
The car is quite ______ of petrol.
A. economic
B. economical
C. saving
D. sparing
______ being late made the boss angry.
A. Him
B. His
C. He's
D. For him