The world is not hungry, but it is thirsty. It seems strange that nearly 3 / 4 of the Earth is covered with water while we say we are short of water. Why? Because about 97% of water on the Earth is sea water which we can't drink or use for watering plants directly (直接地). Man can only drink and use the 3%—the water that comes from rivers and lakes. And we can't even use all of that because some of it has been polluted.
Now more water is needed. The problem is how we can avoid ( 避免) a serious water shortage in the future. First, we should all learn how to save water. Second, we should find out the ways to reuse it. Scientists are making studies in this field. Today, in large cities, water is used only once and then runs to the sea or rivers. In fact, it can be used again.
Finally, the sea seems to be the best answer. There is a lot of water in the sea. All that needs to be done is to get the salt out of the sea water. This is expensive, but it's already used in many parts of the world. Scientists are trying to find a cheaper way of doing it. So you see, if we can find a way out, we'll be in no danger of drying up.
