A:
B:
C:
D:
如图所示,光滑的水平面上,小球m在拉力F作用下做匀速圆周运动,若小球到达P点时F突然发生变化,下列关于小球运动的说法正确的是( )
—When Mum is at home, I have to practice every day, but she is on a business trip this week.
读“亚洲范围略图”,判断下列说法正确的是( )