问题 选择题

关于匀速圆周运动,以下说法不正确的是[ ]

A.匀速圆周运动是变速运动

B.匀速圆周运动是变加速运动

C.向心加速度是描述线速度方向变化快慢的物理量

D.向心力的大小不变,方向总指向圆心,所以向心力为恒力

答案

答案:D

单项选择题

About a week ago, when I was playing basketball at our local park, I noticed a small group of boys picking on a smaller, skinnier boy. They were (21) him names and even pushed him to the ground and kicked dirt in his face. (22) I saw that, I walked over to the group.
I stepped (23) them and the smaller boy, and asked them politely what this boy had done worthy of (24) they were doing to him. One of the boys replied, "He’s weird. " At that, I asked one of the boys if he thought his friend was weird, and the (25) was "No." So, I asked another boy what the word "weird" (26) , and he said, "Different." That was my cue (暗示). I told them that everyone is (27) , and that they all looked just as different to the other boy as he did to them. They all stood (28) for a moment, and then the most amazing thing happened. One of the boys helped the small boy off the ground and then said sorry to him. He (29) to let him play with them.
I thanked the boy for being so (30) As I looked around, I realized that there were dozens of other people at the park (31) no one else had stopped to help this boy. I felt happy that the boy was p enough to stand up against his friends to (32) someone in need, but I felt sad that (33) else had even taken a second look.
I hope that my action helped them (34) that they could have made a difference with a little (35) , and maybe next time they will be the ones who choose to help.

Ⅱ. 完形填空

/Close
通过下面短文,掌握其大意,然后再各题所给的四个选项(A、B、C和D)中选出一个最佳选项。

A.energy

B.practice

C.knowledge

D.effort

判断题