the old book

As we know, when senior students graduate from school, most of their reference books are thrown away, which are still in good condition? What a great waste it is!
I suggest that we should recycle these books. On one hand, recycling them can save a lot of natural resources, which are used to make textbooks. On the other hand, senior students may have made plenty of useful notes on the pages. They are very helpful to the following users.
At present, the whole nation is called on to build an energy-saving society. I think it is certainly meaningful to our long-term interests. In fact, in Australia and some other countries, recycling textbooks is popular, which gives us a good example。