普通交流发电机在高速时,其磁场的产生是靠()
A.它激
B.自激
C.永磁
参考答案:A
― Where do you sit, Peter?
― I sit Millie. She is just on my right.
A.next to
B.in front of
C.before
D.behind
水露点越低,越容易析出水。