Years ago，green was just a color.Now it's much more!In the1970s，some people began to worry about what we did to mother Earth.As a result，green thinking （1）

that/which

that/which

is a big idea that touches governments all over the world，and a small idea that touches us all in our （2）h

omes

omes

.
    Architects（建筑師） and building engineers are thinking about how to make buildings greener.These days，green architecture is becoming more and more （3）p

opular

opular

.We need to be very careful about the materials we use.It is better to （4）c

hoose

hoose

renewable materials--those that the Earth replaces quickly.Or we can reuse some，materials.Also，for those materials that are not renewable，we need to use them as （5）l

ittle

ittle

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 （6）s

pend

pend

time on green buildings.In many cases，green （7）e

nergy

nergy

comfortable for people.For example，natural wind brings people cleaner and fresher air.
    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 （8）h

ealthier

ealthier

.
    Architects must consider what the building will do to the environment.For example，they might try to use as little land as possible.If a building covers a large area，there will be less （9）s

pace

pace

for plants and trees.They also have to think about cutting down waste and （10）p

ollution

ollution

while the building work is going on.
    Although green buildings are more expensive to build，they are less expensive to run.