Many places in the world need more fresh water . Every country is trying to find ways to turn salt water into fresh. Why aren't there many factories like the Symi factory? In some places, the sun isn't hot enough, or it doesn't shine every day. In these places other ways to heating  sea water can be used. These ways cost more money, but they work faster than the sun. By boiling  sea water with high heat,a lot of fresh water can be made quickly. But heating is not the only way to get fresh water from salt water. Other ways are tried. One way is freezing . The fresh part of salt water freezes first. To get fresh water, the pieces of ice are taken out. Which way is best? The one that gives the most water for the least money. It may be a different way for each place. Symi's way seems very good for small, hot places. It doesn't make very much water at a time. But the factory is easy to build and cost little. From the passage we know that fresh water .
is needed in many countries is needed in every country can be used in many ways is very important for factories