质量为的物块沿着直线运动,在外力作用下,其加速度大小逐渐变小。则在这个过程中
A.外力一定做正功
B.位移一定逐渐增加
C.外力的大小一定变小
D.速度的大小一定变小
答案:C
“Well, I’ll tell you a secret ...” said the boy, with his mouth almost _____ my ear.
A.touched
B.touching
C.touch
D.to touch
地形图的识读有哪些基本内容?