带电量分别为2Q,4Q 的两点点电荷,相距为r,相互作用力为F.现把两个电荷的电量各减少一半,距离增大为原来的2倍,则两个点电荷的相互作用力变为( )
A:F
B:F4
C:F8
D:F16
In the second lesson, the teacher still____him to draw an egg, but he____the egg on a plate. Little Leo____unhappy and asked, "____do we draw eggs all the time?" "Look ____. It's an egg again, but it looks____." said the teacher.
形近字组词
清____ 晴____
误____ 蜈____