题目内容
【B20】
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竞争市场环境分析的主要目的是()。
Every animal is a living radiator(散热器) -- heat formed in its cells and given-off through its skin. Warm-blooded animals keep a normal temperature by continuously replacing lost surface heat; smaller animals, which have more skin for every ounce (盎司) of body weight, must produce heat faster than bigger ones. Because small animals burn fuels faster, scientists say they live faster. The speed at which an animal lives is determined by measuring the rate at which it uses oxygen (氧气). A chicken, for example, uses one-half cubic (立方的) centimeters of oxygen every hour for each gram it weighs. Because it uses oxygen eight times as fast, it is said that the mouse is living eight times as fast as the chicken. The smallest of the warm-blooded animal, the humming-bird, lives a hundred times as fast as an elephant. There is a limit to how small a warm-blooded animal can be. A bird that weighs only two and a half grams would starve to death. It would burn up its food too rapidly and would not be able to eat fast enough to supply itself more fuel.
The passage says that every animal is a living radiator because it ______.
【B13】
听力原文：W: Why didn't you come here yesterday, John？
M: I'm sorry, sir. My mother was ill.
What can we learn from the dialogue？
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