Our teacher explained one simple thing: most students do not drink water.
In hot weather, a young person needs about two litres a day.
When we drink too little, we get a and we cannot study well.
Many students sweet drinks, however sugar is not healthy.
Our class made a simple : every student brings a of water to school.
We fill the s with clean water near the office.
After two weeks, the teacher asked us about the change.
Most of us said we were not so in the afternoon.
Water is cheap, and it is the easiest way to feel better.