7.
根据短文内容,完成下列各题。
Our earth is in trouble. (2) Our drinking water is becoming dirtier,
and the air is not as clean as before. People and factories are polluting
the air, rivers and lakes and seas. You may think that there is nothing you can
do to help. That's not true. There are many things you can do to help the
earth. Cars burn gasoline. This will produce a lot of CO2 into the
air. Some people believe that too much CO2 is making the earth
warmer than ever. They think CO2 thins the clouds above us. The
clouds keep us away from the strongest sunlight. So try to walk, ride a bike or
take a bus. And if you drive a car, drive at a steady speed. This can save some
gasoline. The biggest energy use at home is for keeping (1) ___________or____________.
So turn the air conditioner off when you don't need to use it. Use lights that
save energy. Use fewer things that cannot be used again. When you buy
something, consider those made from things that can be used again first. A lot
of water is needed for a shower. In one week a family uses as much water for
showers as a person drinks in three years! Take shorter showers. This can cut
the use of water.