2．Dirty water can be dangerous to drink and make people get ill.It is harmful to the environment and it may hurt the animals.So where is the dirty water from？
Sewage（污水） is a big part of dirty water.In many places，it goes straight into rivers，lakes or seas.Too much sewage will kill fish and other water lives.It makes the water unsafe for animals to drink，wash or swim.So we must let the sewage go into rivers in a right way.
Oil is important，but it may be bad for the environment.If a truck or a ship leaks（泄漏） oil，plants and animals may die.For example，when the birds' bodies are full of oil，they aren't able to fly.Their feathers may no longer protect them from the cold weather.
Factories often pour waste water into rivers.This may do harm to plants，animals and humans.Some factories
filter the waste water before it goes into rivers.In this way，the waste water won't pollute the river and this helps to keep the environment clean.
Smoke and gases from factories and cars in the air may pollute the environment.When it rains，the chemicals in smoke and gases fall down together with the rain.They can kill plants and animals.
As we all know，water is an important part of human life.And the water resources（資源） are not enough on Earth.So we should try our best to save water and protect the valuable water resources in our daily lives.At the same time，we can also encourage more people to join us.
（1）Why do we need to make the sewage go into the rivers rightly？
A.The sewage will look dirty.
B.The sewage will pollute the air.
C.The sewage will kill some animals.
D.The sewage will make the drinking water taste bad.
（2）What does the underlined word "filter" in Paragraph4 mean？
A.Clean.
B.Add.
C.Throw.
D.Produce.
（3）Dirty water comes from the following EXCEPT
.
A.rain with chemicals in smoke and gases
B.sea water
C.waste water
D.sewage and oil
（4）According to the passage，we can save water by doing the following things EXCEPT
.
A.avoiding leaking oil into the environment
B.pouring waste water into rivers in a right way
C.stopping factories from discharging too many harmful gases
D.making drinking water from the sewage
（5）What is the purpose of the passage？
A.To show the importance of gases.
B.To teach people to produce dirty water.
C.To tell people to save animals and plants.
D.To ask people to protect water resources.
