转速、电流双闭环直流调速系统中，电流调节器始终饱和。( )
双闭环调速系统起动时ASR为什么能迅速饱和，而ACR不一定饱和？如果ACR在起动过程中饱和，会出现什么现象？
Which of the following is NOT meant by the author？
Acid rain is found to have affected vast areas of the Northern Hemisphere.
B. A region without industry can still be affected by acid rain.
C. Power plants, automobiles and factories are known to be the major source of acid rain.
D. Terrestrial vegetation is entirely free from acid rain.
A. Because many old people sell their houses after their children leave.B. Be
A. Because many old people sell their houses after their children leave.
Because many old houses in the bad part of the town are not inhabited.
C. Because many young people have moved into comfortable apartments.
D. Because many people have quit their old houses to build new ones.
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