填空题

The stiff up-front cost has always been the biggest barrier to residential use of solar power. An average set of rooftop panels costs $ 20,000 to $ 3.0,000 and takes 10 to 15 years to produce enough electricity to pay for itself--a deal not unlike asking a new cell-phone owner to pay in (47) for a decade’s worth of minutes. But that equation will change as the cost of solar panels drops and the price of fossil-fuel-generated electricity rises. Now solar companies and banks are helping homeowners (48) the cost over the lifetime of the panels,and sunny California is at the forefront of this (49) . In April, SolarCity, one of the biggest panel installers in the state, began (50) no-money-down leases for home installation. PhotovoItaic (光电的) solar installations were up 45% last year compared with 2006,with about a third of those systems going on (51) roofs.
Sure,solar panels are a huge (52) , and credit markets are tightening up. But with carbon caps looming on the horizon and power supplies running (53) ,customers can insulate (使免受) themselves from future electricity shocks.
Still,solar isn’t for every home. Different parts of the U.S.receive (54) different amounts of sunlight,so a solar panel in sun-drenched (充满阳光的) Las Vegas will always be more (55) than one in cloudy Seattle. Incentives (56) from state to state and can tip the numbers as well. But financing means that at least you won’t need a lot of excess money to go green.
A. offering I) advance
B. investment J) potential
C. bringing K) vary
D. stretch L) residential
E. vastly M) productive
F. demand N) rapidly
G. trend O) running
H) short