题目内容：

    You may say that rain comes from clouds, but you can also say that rain is clouds.1., you should know the mechanism through which water moves from the Earth to the atmosphere and back again.

Dew point is the temperature at which water vapor begins to condense (凝结) and becomes water droplets that can fall as rain. Dew point can vary anywhere from the 30s (Fahrenheit) to, on rare occasions, the 80s.

2.. Once the air has cooled past the “dew point", it condenses around a nucleus, which are usually tiny particles of dust, smoke or even salt that are floating in the air. Then tiny water droplets are formed.3.. If you pay close attention to clouds in the sky, you'll see char they’re constantly shrinking and growing,

Water vapor that has formed clouds is on its way to becoming rain, bur it's not there yet. For now, the water droplets are 80 tiny that the air currents keep them in the air, just as swirling particles of dust can stay in the air.4..

When water droplets combine with one another, they become heavier than the uplift of the air around them. Eventually they fall down through the cloud as rain.5.They attract more water vapor to themselves and grow quickly until they're heavy enough to fall as snow.

A.Rain cloud is formed when there is enough water in the air

B.As warm air rises with the water vapor it contains, it cools

C.If you are curious about what kind of cloud will become rain

D.Sometimes the droplets rise high enough to freeze into ice crystals.

E.The tiny water droplets that initially form are what you see as clouds

F.If you want a better understanding of why rain comes down from clouds

G.As those droplets continue to rise, they have two ways to come back to Earth