未分类题

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... Fossil fuels burned to【C1】______cars and trucks,【C2】______homes and businesses, and power factories are【C3】______for about 98% of US carbon dioxide emissions, 24% of methane emissions, and 18% of nitrous oxide emissions. Increased agriculture, deforestation,【C4】______, industrial production, and mining also contribute a significant【C5】______of emissions. In 1997, the United States【C6】______about one-fifth of total global greenhouse gases.
The 20th century' s 10 warmest years all【C7】______in the last 15 years of the century. Of these, 1998 was the warmest year on【C8】______. The snow【C9】______in the Northern Hemisphere and floating ice in the Arctic Ocean have decreaseD.Globally, sea level has【C10】______4～8 inches over the past century. Worldwide precipitation over land has increased by about one percent. The【C11】______of extreme rainfall events has increased throughout much of the United States.
Increasing concentrations of greenhouse gases are likely to【C12】______the rate of climate changE.Scientists expect that the average global surface temperature could rise 1～4.5℉(0.6～2.5℃)in the next fifty years, and 2.2～10℉(1.4～5.8℃)in the next century,【C13】______significant regional variation. Evaporation will increase【C14】______the climate warms,【C15】______will increase average global precipitation. Soil moisture is likely to decline in many regions, and【C16】______rainstorms are likely to become more frequent. Sea level is likely to rise two feet along most of the US coasts.【C17】______of climate change for specific areas are much less reliable than【C18】______ones, and it is unclear【C19】____________regional climate will become more【C20】____________.
【C1】
A.drive
B.operate
C.run
D.motivate