题目

阅读下列短文，从每题所给的四个选项（A、B、C和D）中选出最佳选项。C Bob Smith is old. He has two big houses (房子) and a new car. He has no wife (妻子)， but he is a father of four children. He has two sons and two daughters. One son is from (来自于) Canada. His name is Jack. The other (另一个) is from England. His name is Mike. One of his daughters is from China. Her name is Meimei. The other is from America. Her name is Lucy. Meimei and Lucy are both (都) eleven. Bob Smith is not the children's real father, but he loves them very much. The children lo 下列说法正确的是 [　　] A． 物体在恒力作用下不可能做曲线运动 B． 物体在变力作用下不可能做曲线运动 C． 物体在恒力作用下可能做曲线运动 D． 做圆周运动的物体，合外力一定指向圆心