As we all know, water is essential in our daily life. We drink water every day, we use water to wash things and cook food, we also use water to make machines. People can't live without water.
Though about 75% of the earth is covered with water, only 3% of it is fresh water. So we must save water by having a shower instead of a bath. We can save water by fixing dripping taps immediately and we can also save water by not washing under a running tap.
With the help of the Internet，shopping is not a difficult job. Just click your mouse to choose the article you like，and the shopping is finished. You needn't step out of the room。
It seems easy and quick. But there's always a trap（陷阱）online. If you are careless，it will bring you some trouble. You may find the color of the article is different from what you want，or the size is either too small or too big. If you want to be different，you'd better not buy clothes online. Once you put on the clothes you bought online and go out，you will find many people wear the same clothes in the street。
So you must be careful，because everything has two sides。
Last summer,big floods occurred in both the south and north of China.They were the most serious ones in this century.They caused great loses.Fields were ruined,houses were washed away and many people became homeless.
There are three reasons for the floods.First,it had kept raining for months.Secondly,many forests had been cut down and the soil was washed away.Finally,some lakes had been turned into fields,which seriously blocked the waterways.
Now,some measures have been taken to prevent floods from happening again.The trees along the rivers have been protected;old dams have been rebuilt and some fields have been turned back into lakes again.