根据首字母提示填空。

     Many people now think that teachers give too m   1   tests in class and too m    2     homework after

school. So children do not have any t   3   for other activities. If teachers and parents t   4   to each other

about the problem, they can work it o   5   together. Teachers should t   6   to make the tests e   7   and

create(创作) the homework better. Besides(除此之外), parents should h   8   their children develop(发展) good study habits(习惯) . Then, the students will b   9   happier and h   10   .

静摩擦力是在（）内变动的，在物体处于将要滑动而又尚未滑动的临界状态时，静摩擦力达到最大值，称为最大静摩擦力

A.固定范围

B.一定范围

C.相对范围

D.相对空间