D-4型电铲卷扬电动机的励磁方式为()。
A.自激
B.他激
C.串激
参考答案:B
On Sunday when I was a little boy, father and I_____ get up early and go fishing. [ ]
A, could
B. would
C. might
D. should
我国历史上最后一次大规模修建长城是在()。
A.汉代
B.北朝
C.唐代
D.明代