题干

半潜船可用来运输超大型货物,空载时漂浮于海面(如图甲);装载时需向船体水舱注水,船体重力增加,巨大的甲板下沉至海面以下(如图乙);待货物被拖到甲板上方时,排出水舱中的水,船体重力减小,甲板上浮至海面,完成货物装载(如图丙).半潜船在甲、乙、丙三种状态时所受的浮力分别为F1、F2、F3,则以下判断正确的是(   )

A:F1>F3>F2

B:F2>F3>F1

C:F3>F1>F2

D:F3>F2>F1

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答案(点此获取答案解析)

B

同类题5

阅读下面短文,从短文后各题所给的A、B、C、D四个选项中,选出最佳选项。

    Do you want to be successful in everything you do? If so, then 1? Here is an example.

    There was a farmer who 2 corn(玉米) all his life. Each year he took his corn to the market. Then each time his corn was chosen as the 3 and won the first prize.

    One year a newspaper reporter interviewed him and learned something 4 about how he grew it. The farmer  5 his seed (做种子的) corn to his neighbours.

    "How can you share your best seed corn with your neighbours?" the reporter asked. "You know they are taking part in the 6 with you each year. "

    "Why, sir," said the farmer, "didn't you know? The 7 picks up pollen (花粉) from the corn and moves it quickly from field to field. If my neighbours grow 8 corn, cross-pollination (异花传粉) will affect the quality of my corn. So if I want to grow good corn, I must   9 my neighbours to grow good corn. "

    The farmer knows much about the connection of life.  His corn cannot improve 10 his neighbours' corn improves.

    As a great man says, "We make a living by what we 11; we make a life by what we give." We can't  12 without food, clothes, and many other things. However, a meaningful life is not decided by how much we can get, 13  by how much we can give others. Giving, instead of taking, makes us 14 from other animals.  So those who choose to live well must help others to live well and those who choose to be happy must help others to find 15 in their life.