题干

一物体从某行星表面竖直向上抛出.从抛出瞬间开始计时,得到物体相对于抛出点的位移x与所用时间t的关系如图所示,以下说法中正确的是

A:物体上升的最大高度为16m

B:8s末物体上升到最高点

C:该行星表面的重力加速度大小为4m/s2

D:物体抛出时的初速度大小为4m/

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A

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    Once upon a time, a little fish lived in a pond. But she wanted to go to the forest. The pond was deep, and high banks keep it from the view of the forest. Wanting to see the forest, the fish would jump out of water now and then, reaching 1 over the pond with the strength of her tail. It seemed to her that, with a little more effort, she could fly, but unfortunately each time she would fall right back into the 2.

    The fish's mother—a big fish with kind eyes would 3, “What would you want the forest for? We fish must live in water, and that is the way it is.”

    The fish would answer, “I want to go to the forest and that is my 4. And it must come true.”

    So she went to the little fairy(仙子) who had been friends with her for her whole life and pleaded(恳求), “Oh little fairy! I have been living in the water all the time. Now I am 5 my small world. I want to see those big trees covered with beautiful flowers, leaves and fruits. I want to meet 6 and animals.”

    To make her friend happy, the little fairy swung her little wand(魔杖). The rain started falling on the earth, and a few days later, the forest around the pond was covered with water,

    7 the small pond into a lake. The fish swam to the forest. How 8 it was! The fish was very excited because her dream would come true soon.

    “Hello,” the fish said to the flowers and the trees. She 9 on and saw animals sitting on fallen trees which were sticking out of the water. But as soon as she swam closer to the trees, she saw that all the animals were very sad. “We are without 10. The water has flooded the whole forest,” the animals told the fish 11. All this made the fish very unhappy.

    “I am 12 with this rain but my friends—trees and animals are quite unhappy. Oh little fairy! Please 13 the rain. I will go back to my pond. I will be more pleased when trees, animals and birds are happy,” pleaded the fish. The water began to 14 , and the animals were very glad and ran off, and the fish 15 to the pond and she was happier than ever before.

    The art of happiness is to serve all. To be really happy, we must think not only of how we can help ourselves, but how we can help others.