Theseahasalwaysinterestedman.Fromithecangetfood,mine...
问题详情:
The sea has always interested man. From it he can get food, minerals, and treasure. 36But he could not go far beneath (在......的下方) its surface (表面).
37 However, he is not a fish. He must breathe air, so he can’t stay under the water’s surface for any length of time. To explore deep water, man faces even more dangers and problems.
A diver (潜水员) who wants to stay under water for more than a few minutes must breathe air or a special mixture of gases. 38 He can carry a tank of air on his back and breathe
through a nose and a mouthpiece. Water weighs 800 times as much as air. Tons of water pushes against a diver deep in the sea. 39
When a diver is under great pressure, his blood takes in some of the gases he breathes. Ashe rises to surface, the water pressure becomes less. If the diver rises too quickly, the gases in his blood form bubbles(气泡). The diver is then suffering from the bends (减压病). The bends can cause a diver to double up in pain. 40
A. His body is under great pressure.
B. Scientists are trying to find more about the sea.
C. For thousands of years, he could sail on it.
D. They can even kill him.
E. He can wear a diving suit and have air pumped (抽吸,泵送) to him from above.
F. The water pressure can cause a diver to breathe with difficulty.
G. Man wants to explore deep into the sea.
【回答】
CGEAD
知识点:七选五题型
题型:未分类
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下列加点词注音全对的一项是( )A.浣女(huàn) 谄媚(xiàn) 邂逅(xiè)B.惘然(wǎn...
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对于锌一铜一稀硫*组成的原电池装置中,当导线中有1mol电子通过时,理论上的两极变化是( )。 ①锌片...
问题详情:对于锌一铜一稀硫*组成的原电池装置中,当导线中有1mol电子通过时,理论上的两极变化是( )。 ①锌片溶解了32.5g②锌片增重32.5g③铜片上析出lgH2 ④铜片上析出1molH2 A.①和③ B.①和④ C.②和③ D.②和④【回答】A知识...
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已知铁的一种氧化物,其中含氧元素的质量分数为30%,则这种铁的氧化物的化学式为 ( ) A.FeO ...
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某有机物结构简式为,下列关于该有机物的说法中不正确的是( )A.遇FeCl3溶液显紫*B.与足量的*氧化*溶...
问题详情:某有机物结构简式为,下列关于该有机物的说法中不正确的是()A.遇FeCl3溶液显紫*B.与足量的*氧化*溶液在一定条件下反应,最多消耗NaOH3molC.能发生缩聚反应和加聚反应D.1mol该有机物与溴发生加成反应,最多消耗1molBr2【回答】解析A项,有机物分子中存在*羟基,所以...
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