A:随电压的增大而减小
B:随电压的增大而增大
C:加大两板间距离,时间将减小
D:与电压及两板间距离均无关
如图,三棱台DEF-ABC中,AB=2DE分别为AC,BC的中点.
Last year, three hundred English teachers took part in the ______ English training.