Look at the Earth from space.Why does our planet look so blue？It's blue because water covers almost three quarters（四分之三） of the Earth's surface.Water is not just an important part of our planet.It is an important part of our body，too.More than half of our total（全部 的）body weight is water.
?Our body loses water whenever we exercise or go to the toilet.That's why we need to drink plenty of water every day.We drink water.We use it to cook，clean，and carry waste out of our homes.Farmers use it to grow vegetables and crops（莊稼）like rice and wheat；factories use it to make products.
?Since the 1950s，the amount（數(shù)量）of water people use has increased by three times But the water supply（供應(yīng)）hasn't.Scientists worry that soon there won't be enough water for us，as well as for the animals and plants that share our world.What can we do to help？Use water wisely.
?Having enough water isn't our only problem.We also need it clean.
?Right now，ships and factories are putting wastes into seas，rivers and so on.Even chemicals（化學(xué)制品）that farmers use are running into rivers and lakes.All this pollution can make the water dangerous to drink.It can also harm fish and other water-living lives.We must do something to stop pollution.It's the best way to protect our world's most valuable natural resource（資源）.

（1）

C

C

of the Earth's surface is covered by water.
A．Almost 50%
B．Less than 50%
C．Almost 75%
D．Over 75%
（2）How many kinds of water are mentioned in Paragraph 1（第一段）？

B

B

A．One
B．Two
C．Three
D．Four.
（3）From the third paragraph，we can infer that

D

D

.
A．we don't have enough water to use since the 1900s
B．there are more people than before
C．there will be less animals in the future
D．it's necessary for us to save water in our daily life
（4）What is the purpose of the passage？

A

A

A．To ask people to value water.
B．To introduce the uses of water.
C．To advise people to drink more water.
D．To describe the situation of water supply.