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【C20】
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A．The woman should wear his scarf to the game.B．It will be cold at the game.C．The woma
A．Places where T-shirts are not acceptable.B．Images that are currently printed on T-sh
According to the passage, one important reason why newspapers printed daily weather maps during the first half of the twentieth century was
听力原文： A number of insects rely on leaping or jumping as a way of escaping from enemies. Grosshoppers probably have the most remarkable jumping ability of all these insects. If we think of it in human terms, a grosshopper's high jump is like a human jumping over a five story building. Imagine that a person jumping over a five story building. Well, we'll take a look at the structure of grosshopper's leg to see why it's able to jump so well, but first I wanna talk about the sensory organ that tells grosshoppers when to jump in the first place. En, OK, a grosshopper has two sensory organs located at the end of its abdomen. Whenever these organs sense of change in air pressure which might be produced by an enemy approaching, and impulses transmitted to the legs, this first impulse deactivates the nerves that control normal working and sets the grasshopper's jumping muscles into a sort of pre-jumping position. Now at this point, if the sensory organs don't detect additional air pressure changes, the jumping muscles relax and a grosshopper goes back to its normal walking, but if the organs continue to send danger, another set of impulses put the jumping muscles in motion. The distance of the jumping is determined by just how many impulses are transmitted in the second set, the more impulse the longer the jump. OK now let's see why the grosshopper can jump so far. Open your books at the part of that muscle structure of the grasshopper's leg. I think it's in chapter 9.
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