Years ago, green was simply a color. Now it’s much more! In the 1970s, some people began to worry about what we did to mother Earth. ___1___ It is a big idea that touches governments all over the world, and a small idea that touches us all in our homes.

Architects (建筑师) and building engineers are thinking about how to make buildings greener. These days, green architecture is becoming more and more popular. ___2___

We need to be very careful about the materials (材料) we use. It is better to choose renewable materials-those that the Earth replaces quickly. ___3___ Also, for those materials that are not renewable, we need to use them as little as possible. Our mother Earth has offered us many other possibilities, such as wind and solar power.

Planners must think about the needs of those who will spend time in green buildings. In many cases, green energy is more comfortable for people. ___4___ Natural lighting is often kinder to the eyes than electric lighting. In fact, many people who live or work in green buildings report feeling happier and healthier.

___5___ For example, they might try to use as little land as possible. If a building covers a large area, there will be less space for plants and trees. They also have to think about cutting down waste and pollution while the building work is going on.

Although green buildings are more expensive to build, they are less expensive to run.

A. Or we can reuse some materials.

B. As a result, green thinking was born.

C. To understand it, we have to look at three different areas.

D. For example, natural wind brings people cleaner and fresher air.

E. Architects must consider what the building will do to the environment.