物体的初速度是v0，以加速度a做匀加速直线运动，如果要使速度增加到初速度的n倍，则经过的位移是[ ]
A.
B.
C.
D.
答案：A
Wu baoguo , a teacher from the mountain , devoted all his life ______ children . [ ]
A. educate
B. to educate
C. to educating
D. to education
接触线拉出值的布置应符合设计要求，允许偏差±（）mm。
A.10
B.20
C.30
D.50
to education