About twenty percent of the world’s present energy already (1)..... from the sun in one form or another. Special devices have already been made (2)..... to place on the roofs of houses and flats to (3)..... the sun’s rays. Thousands of these devices are now being used to provide (4).... in homes throughout the United State.(5).... more than a million solar (6)... units have already been built in home in Japan. Other purposes (7)... which solar energy is at present being used include the (8)... of salt from seawater, irrigation and sewage disposal. For most people in developing countries,the (9)...is not for airconditioners or central heating (10)...for cheap ways of cooking food,drying crops and lighting homes 1, A.goes B.comes C.makes D.supplies 2, A.difficult B.effective C.available D.valuable 3, A.collect B.store C.give off D.produce 4, A.electricity B.source C.fuel D.power 5, A.where B.when C.while D.which 6, A.water-heat B.water-heating C.heat-water D.heat-watering 7, A.for B.at C.from D.by 8, A.relation B.production C.provision D.separation 9, A.supply B.lack C.need D.response 10, A.then B.but C.as D.also