质点在平面内从P运动到Q，如果用v、a、F表示质点运动过程中的速度、加速度和受到的合外力，下列图示正确的是（   ）

选择方框中所给词语的适当形式填空, 使短文正确，通顺，连贯。每词限用一次。(每空1分， 共10分)

There is nothing more【小题1】  than the sun. Without the sun, all【小题2】  things on the earth will【小题3】.

The sun is a star. In the sky there【小题4】  thousands of stars like the sun. They are as large as the sun and as hot as the sun. At night you can see many stars,【小题5】  in the daytime you can only see one star, the sun.

The sun is much nearer to us than any other star. This is【小题6】  it looks biggest and    __小题1: of all the stars. The distance of the sun from the earth is as much as 150【小题8】__  kilometers. Most of the stars are thousands of light years（光年）away from the earth.

Do you know the light year? Nothing in the world travels faster than light. It    __小题2:__ at 300, 000小题3:a second. And one light year is the distance that light travels in one year.