人們總以為淡水是取之不盡的，實(shí)際上淡水資源是很有限的。

It is generally believed that there is a good supply of fresh water. But to our disappointment, the fact is just the opposite.
As we can see, the world population is growing rapidly day by day. So enough fresh water is needed to feed such a big population. What’s more, with the development of industry, factories and vehicles produce poisonous gases or wastes, which consequently results in the pollution of water. Though fresh, a good amount of it can no longer be used. Only quite limited fresh water resource is available to human beings. So it’s high time for us human beings to take quick action to protect water resource. Stop pollution and save water, otherwise, we cannot survive on the earth.
With fresh water, the world will be prosperous.