在 1:1000000的地图上,实际相距为 200 km的两地,图上距离是( )cm.
20
—Look! There so many people in the park.
—Nobody likes to stay at home ______ Sunday morning.[ ]
A. in
B. on
C. at
D. to
发电机的无功负荷是当电动机带动机械负荷时,在电磁能量转换过程中磁场所消耗的功率。