如图所示,在水平面上固定一个半径为R的光滑球体,球的最高点处有一个小物体,现给小物体一个水平初速度,要使物体不沿球面下滑而做平抛运动,球落地点C到A点的最小距离。
2R
-Your daughter has two children, doesn't she?
-That's right.She ________ in 1972.[ ]
A.did marriage
B.was married
C.married with John
D.got married
水环境规划的类型。