Weather changes when the temperature and the amount of water in the atmosphere change. We can see and feel water coming from the atmosphere when we have rain. But the water must somehow get back to the atmosphere. Meteorologists call this the water cycle.
There are many stages in the water cycle. Rain falls when water vapour in clouds condenses(凝结). Drops of water form and fall to the ground. The water soaks into the ground and feeds streams and rivers. A lot of rain falls into the sea. The heat of the sun evaporates some of the water in the ground and in the rivers, lakes, and the sea. It changes the liquid water into water vapour. The vapour rises onto the air. Water vapour is normally invisible. On a very damp or humid day, however, you can sometimes see water vapour rising from a puddle(水坑) or pond in a mist(薄雾) above the water. Water vapour also gets into the air from living things. Trees and other plants take in water through their roots and give off water vapour from their leaves. People and land animals drink water and breathe out water vapour. In all these ways the water returns to the air. There it gathers to form clouds and condenses to form rain. The rain falls to earth, and the cycle starts again. It continues even if snow or hail(冰雹) fall instead because both eventually melt to form water. The amount of water vapour in the air depends on the temperature. The air is more moist(潮湿) in the tropics(热带) than in the cold polar regions.
小题1: What is the main idea of the passage?
A．Water cycle.
B．Water vapour.
C．How rain forms.
D．Water, vapour, rain.小题2:How many ways of the water returning to the air are discussed in the text?
A．Two.
B．Three.
C．Four.
D．Five.小题3:Whether water vapour can be seen or not depends on _______.
A．how much water is evaporated
B．how good your eyes are
C．in which way water is evaporated
D．climate or weather小题4: From the passage we get to know _______.
A．there is more water vapour in the air in the tropics than in cold polar regions
B．there is more water vapour in the air in cold polar region than in the tropics
C．it gets more rain in the tropics than in cold polar regions because there is less vapour
D．the amount of water vapour in the air depends on how often it rains
小题1:A
小题2:B
小题3:D
小题4:A
本文阐述了水循环的全过程。
小题1:主旨题。文章第1段，特别是最后一句Meteorologists call this the water cycle. 已点明主题。
小题2:判断题。读完第2段，不难发现水返回空中的方式有3种：第1种是太阳蒸发地面上的水使之变成水蒸气返回空中；第2种是树和植物释放出的水蒸气；第3种是人和动物呼出的水蒸气。
小题3:语义理解题。从第2段第9句话On a very damp or humid day, however, you can sometimes see water vapour rising from a puddle(水坑) or pond in a mist(薄雾) above the water. 可以找到为什么。
小题4:判断题。根据最后一句话The air is more moist(潮湿) in the tropics(热带) than in the cold polar regions 可知答案。