One can understand from the passage that …………

In the United States and in many European countries, there is a serious problem. What should be done with the garbage? There is no more room for garbage dumps. It is not possible to burn garbage, because that pollutes the air. So the governments are looking for ways to reduce the amount of garbage that is produced. One way to do this is to recycle as much as possible. Not all kinds of garbage can be recycled, of course. The easiest things to recycle are probably glass and paper. However, one can also recycle many kinds of metal and plastic. Many cities now require people to recycle these materials. The people must put them separately from the regular garbage. Then special trucks take them away and bring them to private companies. These companies will buy them and use them again.