Question 12 is based on the conversation you have just heard.

W: Why is it important to recycle?

M: There are many reasons. Recycling is one way to keep waste out of landfills. Landfills are places to dump waste. (9) But they are unpopular, because they can pollute the soil used to cover them and that’s bad for people who may build new homes there. Recycling also reuses valuable raw materials, such as aluminum and paper. Finally, recycling can leave a lower garbage bill. Recycling lowers the amount of waste put into landfills, therefore, less money is spent for garbage disposal.

W: How has recycling changed over the years?

M: (10) Ten or twenty years ago, you could buy milk in returnable, refillable, glass bottles, and many people recycled voluntarily. Now you buy milk and other products in plastic bottles or paper containers. Because of the high cost of disposing of these things in landfills, many city governments now have recycling programs.

W: How does recycling help the environment?

M: (11) Recycling helps the environment mainly by saving energy. For example, it takes 95 percent less energy to produce recycled aluminum than to produce new aluminum.

W: Can one person really make a difference? If only a few people recycle, then what’s the point?

M: If not you, then who? (12) If we combine our efforts, we can make a difference. Each of us contributes to the waste problem. All the millions of tons of waste that go into landfills started as an old pair of slippers, a broken TV set, or a used magazine that came from somebody’s house—maybe yours!

(12). Why does the man say everybody should make an effort to recycle?

解析：细节理解题。问题为：为什么男士认为所有人都应该为回收做出努力？根据原文If we combine our efforts, we can make a difference. Each of us contributes to the waste problem.可知，如果一起努力，我们可以做出很大的改变，我们每个人都能帮助解决垃圾问题。B选项（我们共同的努力可以产生很大的改变）与原文完全一致。