题目

完形填空     Several days ago, some students from the US visited our school. When we talked, I discovered   1   differences in school life between the US and China. For example, each class   2   fifty minutes in the US. It is a little   3   than that in China. We usually have forty or forty-five minutes in each class. Another difference is that they have less break time between   4  . Besides, although most schools in both countries finish their   5   classes at 12 o’clock, the students in the US only have an hour-long break, so they   6   eat lunch quick关于力与运动，下列说法正确的是A. 力是改变物体运动的原因B. 力是维持物体运动的原因C. 运动的物体一定受到力的作用D. 没有力的作用运动物体就会慢慢停下来