Water is a unique substance. Our bodies contains 70%of water. It is around us in the lakes, rivers, oceans, even in the kitchen tap. We can’t live without it. You have to drink about 1 liters of water every day to be healthy. It doesn’t have taste or colour, but a cup of water is the most delicious drink in a hot day. People always use water in their life, industry, even religion. We produce a lot of waste water, it goes into rivers or lakes. Let’s think about future and try to keep water clean.