Now natural materials are becoming more difficult to be found, many countries are looking for other ways of keeping materials. Recycling becomes more and more important. In order to save energy, in some countries, waste paper, cars and many other things have been recycled and again used in many different ways for many years.
In the USA, a publishing company has brought out several books on pollution and waste in the United States. The books are made of recycled paper—the paper that has been used as paper before. In this way, several thousand trees are saved. One clever schoolboy has worked out that if every schoolbook in the USA was recycled, there would be enough paper for fifty packets of peanuts(花生的包装)for every child in the world for five years.
Several companies are trying to make containers(集装箱)from a hard plastic material. When containers are finished, they can be used as building materials. If mountains of empty cans all over the world can be changed into building materials, houses are not too expensive and there would be a new source of material.
