如何提高发电机的电压?()
A.增加定子中线圈匝数
B.增加转子转速
C.增加转子磁场强度
D.以上都对
参考答案:D
The millions of calculations involved, had they been done by hand, () all practical value by the time they were finished.
A. had lost
B. would have lost
C. would lose
D. should have lost
国际奥委会中唯一的中国人是谁?()