题干

下列说法正确的是(   )

A:某有机物燃烧只生成CO2和H2O,且二者物质的量相等,则此有机物的组成为CnH2n

B:一种烃在足量的氧气中燃烧并通过碱石灰,减少的体积就是生成水蒸气的体积

C:某气态烃CxHy与足量O2恰好完全反应,如果反应前后气体体积不变(温度>100℃),则y=4,若体积减少,则y>4,否则y<4

D:相同质量的烃,完全燃烧,消耗的O2越多,则烃中氢元素的百分含量越高

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D

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    A baby giraffe is born 10 feet high and usually lands on its back. Bringing a giraffe into the world is a tall order. In his book, A View from the Zoo, Gary Richmond describes how a new-born giraffe learns its first lesson.

    The mother giraffe lowers her head long enough to take a quick look. Then she puts herself directly over her child. She waits for about a minute, and then she does the most unreasonable thing. She throws her long leg and kicks her baby, so that it's sent sprawling (四脚朝天).

    When it doesn't get up, what the mother has done is repeated again and again. The struggle (挣扎) to rise is important. As the baby giraffe grows tired, the mother kicks it again. Finally, it stands for the first time. Then the mother giraffe kicks it off again. Why? She wants it to remember how it can get up. In the wild, a baby giraffe must be able to get up as quickly as possible to stay with its group, where there's safety.

    Another writer named Irving Stone understood this. He spent a lifetime studying great people, writing stories about such men as Michelangelo, Vincent van Gogh, Sigmund Freud, and Charles Darwin.

    Stone was once asked if he had found something unusual about these great people. He said, “I write about people who sometime in their life have a dream of something. They're beaten over the head, knocked down and for years they get nowhere. But every time they stand up again. And at the end of their lives they've realized some small parts of what they set out (着手) to do.”