Heating and cooling equipment may be the biggest users of energy in American homes.And homes are responsible for about one fourth of the nation's total energy use.But there are surprisingly simple ways to deeply cut energy use，its effect on the environment and its cost.
David Peabody and his team at Peabody Architects design passive homes.He says the design of a passive house aims to reduce energy demand to its lowest possible level.Passive houses use no solar，geothermal or wind energy equipment.But they are extremely energy efficient.
Mr Peabody says passive houses cut heating and cooling costs by about ninety percent.But what sets his design apart from other “green homes” is that it looks like any other home.
Peabody Architects says it is building the first passive home in the Washington DC area.But it will not be the last.In Arlington，Virginia，Roger Lin and his brother Eric are also building one.Roger Lin of Southern Exposure Homes explains that windows are sealed against leaks and have three layers of glass.
The wind
ows are airtight.On a cold winter day，the temperature inside the unfinished home is a comfortable twelve degrees，or fifty degrees Fahrenheit.
David Peabody says you can find passive homes all over the world.“North Africa，for example，has a passive house community designing for very hot dry climates.”The first passive design was an apartment building in Darmstadt，Germany. Two physicists helped develop it about twenty years ago.
Passive houses use some specialized materials.These include precast concrete panels and insulation. They also need to have special air treatment systems.Supporters say they cost only about five to eight percent more than traditional homes.
But they use ten percent of the energy for heating a
nd cooling.
1．Which of the following is the advantage of passive houses?
A．They cost much less than traditional houses.
B．They look much like the other houses.
C．They are extremely energy efficient.
D．They are more comfortable than other houses.
2．What can be implied in the passage?
A．Passive homes can be found everywhere in the world.
B．Passive homes are specially built for winter use.
C．The construction of passive homes takes advantage of high technology.
D．“Green homes” differ from traditional homes in their appearances.