Man has been interested in robots for quite some time. Scientists are always inventing new and good robots, which will play an important role in our future lives.

    ____

    They will take over jobs such as preparing meals, washing dishes, and sweeping the floor, so that we will have more free time to have fun.

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    They will do all the heavy and dangerous work, and be put in hospitals, schools and offices.

    ____

    Whenever we feel sad, lonely or upset, we can have a chat with a robot. Robots will not only be good friends but they will also offer us good advice.

    In conclusion, robots will be more and more intelligent and will benefit us in many ways.

A. Robots will be our friends.

B. Robots will help us with our work.

C. Robots will be of help in doing housework.

D. Robots will replace humans in many ways.

1952年底中国土地改革基本完成后，（    ）

如图所示，一人骑自行车以速度V通过一半圆形的拱桥顶端时，关于人和自行车受力的说法正确的是（    ）