Our city has developed into a big city,w

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问题选择题

Our city has developed into a big city,which is______it used to be.

A．four times larger than that

B．four times the size of what

C．four times the size larger than what

D．as four times the size as that

答案

答案：B

填空题

根据我国的四大地理区域图中所表达的内容可以看出，我国疆域辽阔，不同地区的_________差别很大。界线B大致和_____mm等降水量线、____℃等温线最接近。

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阅读理解

What makes it rain? Rain falls from clouds for the same reason anything falls to Earth. The Earth's gravity pulls it. But every cloud is made of water droplets or ice crystal(冰晶). Why doesn't rain or snow fall constantly from all clouds? The droplets or ice crystals in clouds are extremely small. The effect of gravity on them is slight. Air currents move and lift droplets so that the net downward amount of water is zero, even though the droplets are moving constantly.

It can be seen that droplets and ice crystals behave somewhat like dust in the air in a beam of sunlight. To the casual observer, dust seems to act in a totally random fashion, moving about

without fixed direction. But in fact dust particles（分子） are much larger than water droplets and they finally fall. The average size of a cloud droplet is only 0.0004 inch in diameter（直径）. It is so small that it would take sixteen hours to fall half a mile in perfectly still air, and it doesn't fall out of moving air at all. Only when the droplet grows to a diameter of 0.008 inch or larger can it fall from the cloud. The average raindrop contains a million times as much water as a tiny cloud droplet. The growth of a cloud droplet to a size larger enough to fall out is the cause of rain and other forms of precipitation. This important growth process is called "coalescence".