A．expand B．exceptions C．historic D．incredibly E．powering F．protectG．reduced H．replace I．sense J．varied K．enormous When we think of green buildings，we tend to think of new ones-the kind of high-tech，solar-paneled masterpieces that make the covers of architecture magazines．But the US has more than 100 million existing homes，and it would be （11） ____ wasteful to tear them all down and （12） ____ them with greener versions．A（n ）（13） ____ amount of energy and resources went into the construction of those houses．And it would take an average of 65 years for the（14） ____ carbon emissions from a new energy-efficient home to make up f or the resources lost by destroying an old one．So in the broadest （15） ____ ，the greatest home is the one that has already been built．But at the same time，nearly half of US carbon emissions come from heating，cooling and （16） ____ our homes，offices and other buildings．"You can't deal with climate change without dealing with existing building，"says Richard Moe，the president of the National Trust．With some （17） ____ ，the oldest homes tend to be the least energy-efficient．Houses built before1939use about 50% more energy per square foot than those built after 2000，mainly due to the tiny cracks and gaps that （18） ____ over time and let in more outside air．Fortunately，there are a vast number of relatively simple changes that can green older homes，from （19） ____ ones like Lincoln's Cottage to your own postwar home．And efficiency upgrades can save more than just the earth，they can help（20） ____ property owners from rising power costs．

A．expand   B．exceptions  C．historic  D．incredibly  E．powering  F．protect G．reduced   H．replace   I．sense     J．varied     K．enormous

When we think of green buildings，we tend to think of new ones-the kind of high-tech，solar-paneled masterpieces that make the covers of architecture magazines．But the US has more than 100 million existing homes，and it would be （11） ____ wasteful to tear them all down and （12） ____  them with greener versions．A（n ）（13） ____  amount of energy and resources went into the construction of those houses．And it would take an average of 65 years for the（14） ____ carbon emissions from a new energy-efficient home to make up f or the resources lost by destroying an old one．So in the broadest （15） ____ ，the greatest home is the one that has already been built．But at the same time，nearly half of US carbon emissions come from heating，cooling and （16） ____ our homes，offices and other buildings．"You can't deal with climate change without dealing with existing building，"says Richard Moe，the president of the National Trust．
With some （17） ____ ，the oldest homes tend to be the least energy-efficient．Houses built before1939use about 50% more energy per square foot than those built after 2000，mainly due to the tiny cracks and gaps that （18） ____ over time and let in more outside air．
Fortunately，there are a vast number of relatively simple changes that can green older homes，from （19） ____  ones like Lincoln's Cottage to your own postwar home．And efficiency upgrades can save more than just the earth，they can help（20） ____ property owners from rising power costs．