【正确答案】
B
【答案解析】[解析] 29-32
Most people think of a greenhouse as a special glass structure used to grow plants all year long. Now the word has a quite different meaning. A greenhouse is less harmful to the environment than other houses.
Greenhouses are designed to be sustainable. They provide people today with what they need and they don't use up or damage the natural resources needed in the future. For years, architects in many areas of the world have designed and built them for environmental activists. However, rapidly rising energy costs are increasing the demand worldwide for houses that use less energy and other resources.
Scientists have pointed out that there are some rules to achieve sustainability. The first and the most important is to stop depending on energy from fossil fuels. Instead, green buildings use the sun's energy as much as possible for heat and power. The second rule is to make sure the air inside a home is healthy and clean. And the third one is to use the land responsibly. Build smaller houses and keep as much natural land as possible around them.
In many American cities, there are new stores that sell parts of old houses and other buildings. The materials are sold at low cost. People re-use them in their homes or businesses. This helps the environment because something new does not have to be manufactured and the old materials don't have to be buried or destroyed. As one storekeeper says, "I believe that re-using materials is the greenest thing you can do. "
29. In the opinion of most people, what does a greenhouse probably stand for?