单选题Over the past decades, sea ice _____ in the Arctic(北极) as a result of global warming.Ahad decreasedBwill decreaseChas been decreasingDis decreasing
单选题
Over the past decades, sea ice _____ in the Arctic(北极) as a result of global warming.
A
had decreased
B
will decrease
C
has been decreasing
D
is decreasing
参考解析
解析：
过去的数十年间，北极的海冰由于全球变暖一直在变少。本句考查时态。通过句首的时间状语over the past decades，以及冰川依然在递减的常识，可知应该选用现在完成进行时，故选C。
过去的数十年间，北极的海冰由于全球变暖一直在变少。本句考查时态。通过句首的时间状语over the past decades，以及冰川依然在递减的常识，可知应该选用现在完成进行时，故选C。
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共用题干New research from NASA scientists suggests emissions of black soot after the way sunlight re- flects off snow.According to a computer simulation,black soot may be responsible for 25 percent of observed global warming over the past century. Soot in the higher latitudes（维度）of the Earth,where ice is more common , absorbs more of the sun's energy and warmth than an icy,white background. Dark-colored black carbon,or soot, absorbs sunlight,while lighter colored ice reflects sunlight.Soot in areas with snow and ice may play an important role in climate change.Also,if snow and ice covered areas begin melting,the warming effect increase,as the soot becomes more con-centrated on the snow surface.“This provides a positive feedback,as glaciers and ice sheets melt, they tend to get even dirtier.”said Dr. James Hansen,a researcher at NASA's Goddard Institute for Space Studies,New York.Hansen found soot's effect on snow albedo（反照率）,which may be contributing to trends to-ward early springs in the Northern Hemisphere,such as thinning Arctic sea ice and melting glac-iers permafrost. Soot also is believed to play a role in changes in the atmosphere above the oceans and land.“Black carbon reduces the amount of energy reflected by snow back into space,thus heating the snow surface more than if there were no black carbon,”Hansen said. Soot's increased absorp-tion of solar energy is especially effective in warming the world's climate.“ This forcing is unusual-ly effective,causing twice as much global warming as a carbon-dioxide forcing of the same magni-tude.”Hansen noted.Hansen cautioned,although the role of soot in altering global climate is substantial,it does not alter the fact that greenhouse gases are the primary cause of climate warming during the past century .Such gases are expected to be the largest climate forcing for the rest of the century.The researchers found that observed warming in the Northern Hemisphere was large in the winter and spring at middle and high latitudes. These observations were coherent with the researchers' climate model situations,which showed some of the largest warming effects occurred when there were heavy snow cover and sufficient sunlight. What is the main cause of climate warming during the past century?A: Soot.B: Snow.C: Greenhouse gases.D:.Wind.
共用题干第一篇Arctic MeltEarth’s North and South Poles are famous for being cold and icy.Last year,however,the amnount of ice in the Arctic Ocean（北冰洋）fell to a record low.Normally,ice builds in Arctic waters around the North Pole each winter and shrinks（缩小）during the summer. But for many years,the amount of ice left by the end of summer has been declining.Since 1979,each decade has seen an 11.4 percent drop in end?of-summer ice cover. Between 1981 and 2000,ice in the Arctic lost 22 percent of its thickness,becoming I.13 meters thinner.Last summer,Arctic sea ice reached its thinnest levels yet.By the end of summer 2007,the ice had shrunk to cover just 4.2 million square kilometers.That's 38 percent less area than the average cover at that time of year. And it's a very large 23 percent below the previous record low,which was set just 2 years ago. This continuing trend has made scientists concerned.There may be several reasons for the ice melt, says Jinlun Zhang, an oceanographer（海洋学家）at the University of Washington at Seattle.Unusually strong winds blew through the Arctic last summer. The winds pushed much of the ice out of the central Arctic,leaving a large area of thin ice and open water.Scientists also suspect that fewer clouds cover the Arctic now than in the past.Clearer skies allow more sunlight to reach the ocean.The extra heat warms both the water and the atmosphere.In parts of the Arctic Ocean last year,surface temperatures were 3.5℃warmer than average and 1.5℃warmer than the previous record high.With both air and water getting warmer,the ice is melting from both above and below. In some parts of the Beaufort Sea,north of Alaska and western Canada,ice that measured 3.3 meters thick at the beginning of the summer measured just 50 centimeters by season's end.The new measurements suggest that melting is far more severe than scientists have seen by just looking at ice covcrfrom above,says Donald K. Perovich,a geophysicist at the U.S.Army Cold Regions Researchand Engineering Laboratory in Hanover,N.H.Some scientists fear that the Arctic is stuck in a warming trend from which it may never recover.By the end of summer 2007 the ice cover in the Arctic was ________.A:4.2 million square kilometersB:11.4 million square kilometersC:1.13 million square kilometers D:38 million square kilometers
共用题干第一篇Arctic MeltEarth’s North and South Poles are famous for being cold and icy.Last year,however,the amnount of ice in the Arctic Ocean（北冰洋）fell to a record low.Normally,ice builds in Arctic waters around the North Pole each winter and shrinks（缩小）during the summer. But for many years,the amount of ice left by the end of summer has been declining.Since 1979,each decade has seen an 11.4 percent drop in end?of-summer ice cover. Between 1981 and 2000,ice in the Arctic lost 22 percent of its thickness,becoming I.13 meters thinner.Last summer,Arctic sea ice reached its thinnest levels yet.By the end of summer 2007,the ice had shrunk to cover just 4.2 million square kilometers.That's 38 percent less area than the average cover at that time of year. And it's a very large 23 percent below the previous record low,which was set just 2 years ago. This continuing trend has made scientists concerned.There may be several reasons for the ice melt, says Jinlun Zhang, an oceanographer（海洋学家）at the University of Washington at Seattle.Unusually strong winds blew through the Arctic last summer. The winds pushed much of the ice out of the central Arctic,leaving a large area of thin ice and open water.Scientists also suspect that fewer clouds cover the Arctic now than in the past.Clearer skies allow more sunlight to reach the ocean.The extra heat warms both the water and the atmosphere.In parts of the Arctic Ocean last year,surface temperatures were 3.5℃warmer than average and 1.5℃warmer than the previous record high.With both air and water getting warmer,the ice is melting from both above and below. In some parts of the Beaufort Sea,north of Alaska and western Canada,ice that measured 3.3 meters thick at the beginning of the summer measured just 50 centimeters by season's end.The new measurements suggest that melting is far more severe than scientists have seen by just looking at ice covcrfrom above,says Donald K. Perovich,a geophysicist at the U.S.Army Cold Regions Researchand Engineering Laboratory in Hanover,N.H.Some scientists fear that the Arctic is stuck in a warming trend from which it may never recover.It can be learned from the last sentence that _________.A:the ice melt in the Arctic may never stopB:scientists are trying hard to stop the ice melt in the ArcticC:scientists are delighted to find out what is going on in the ArcticD:the warming trend in the Arctic can be reversed in the near future
共用题干New research from NASA scientists suggests emissions of black soot after the way sunlight re- flects off snow.According to a computer simulation,black soot may be responsible for 25 percent of observed global warming over the past century. Soot in the higher latitudes（维度）of the Earth,where ice is more common , absorbs more of the sun's energy and warmth than an icy,white background. Dark-colored black carbon,or soot, absorbs sunlight,while lighter colored ice reflects sunlight.Soot in areas with snow and ice may play an important role in climate change.Also,if snow and ice covered areas begin melting,the warming effect increase,as the soot becomes more con-centrated on the snow surface.“This provides a positive feedback,as glaciers and ice sheets melt, they tend to get even dirtier.”said Dr. James Hansen,a researcher at NASA's Goddard Institute for Space Studies,New York.Hansen found soot's effect on snow albedo（反照率）,which may be contributing to trends to-ward early springs in the Northern Hemisphere,such as thinning Arctic sea ice and melting glac-iers permafrost. Soot also is believed to play a role in changes in the atmosphere above the oceans and land.“Black carbon reduces the amount of energy reflected by snow back into space,thus heating the snow surface more than if there were no black carbon,”Hansen said. Soot's increased absorp-tion of solar energy is especially effective in warming the world's climate.“ This forcing is unusual-ly effective,causing twice as much global warming as a carbon-dioxide forcing of the same magni-tude.”Hansen noted.Hansen cautioned,although the role of soot in altering global climate is substantial,it does not alter the fact that greenhouse gases are the primary cause of climate warming during the past century .Such gases are expected to be the largest climate forcing for the rest of the century.The researchers found that observed warming in the Northern Hemisphere was large in the winter and spring at middle and high latitudes. These observations were coherent with the researchers' climate model situations,which showed some of the largest warming effects occurred when there were heavy snow cover and sufficient sunlight. The largest warming effects happened in the Northern Hemisphere with_____.A: thin sea ice and insufficient sunlightB: light、 snow cover and sufficient sunlightC: heavy snow cover and sufficient sunlightD:.thick sea ice and sufficient sunlight
共用题干New research from NASA scientists suggests emissions of black soot after the way sunlight re- flects off snow.According to a computer simulation,black soot may be responsible for 25 percent of observed global warming over the past century. Soot in the higher latitudes（维度）of the Earth,where ice is more common , absorbs more of the sun's energy and warmth than an icy,white background. Dark-colored black carbon,or soot, absorbs sunlight,while lighter colored ice reflects sunlight.Soot in areas with snow and ice may play an important role in climate change.Also,if snow and ice covered areas begin melting,the warming effect increase,as the soot becomes more con-centrated on the snow surface.“This provides a positive feedback,as glaciers and ice sheets melt, they tend to get even dirtier.”said Dr. James Hansen,a researcher at NASA's Goddard Institute for Space Studies,New York.Hansen found soot's effect on snow albedo（反照率）,which may be contributing to trends to-ward early springs in the Northern Hemisphere,such as thinning Arctic sea ice and melting glac-iers permafrost. Soot also is believed to play a role in changes in the atmosphere above the oceans and land.“Black carbon reduces the amount of energy reflected by snow back into space,thus heating the snow surface more than if there were no black carbon,”Hansen said. Soot's increased absorp-tion of solar energy is especially effective in warming the world's climate.“ This forcing is unusual-ly effective,causing twice as much global warming as a carbon-dioxide forcing of the same magni-tude.”Hansen noted.Hansen cautioned,although the role of soot in altering global climate is substantial,it does not alter the fact that greenhouse gases are the primary cause of climate warming during the past century .Such gases are expected to be the largest climate forcing for the rest of the century.The researchers found that observed warming in the Northern Hemisphere was large in the winter and spring at middle and high latitudes. These observations were coherent with the researchers' climate model situations,which showed some of the largest warming effects occurred when there were heavy snow cover and sufficient sunlight. Which of the following statements of soot is NOT true?A: It absorbs sun's heat.B: It is responsible for climate change.C: It reflects sunlight.D:.It may account for a quarter of global warming over the past century.
共用题干第一篇Arctic MeltEarth’s North and South Poles are famous for being cold and icy.Last year,however,the amnount of ice in the Arctic Ocean（北冰洋）fell to a record low.Normally,ice builds in Arctic waters around the North Pole each winter and shrinks（缩小）during the summer. But for many years,the amount of ice left by the end of summer has been declining.Since 1979,each decade has seen an 11.4 percent drop in end?of-summer ice cover. Between 1981 and 2000,ice in the Arctic lost 22 percent of its thickness,becoming I.13 meters thinner.Last summer,Arctic sea ice reached its thinnest levels yet.By the end of summer 2007,the ice had shrunk to cover just 4.2 million square kilometers.That's 38 percent less area than the average cover at that time of year. And it's a very large 23 percent below the previous record low,which was set just 2 years ago. This continuing trend has made scientists concerned.There may be several reasons for the ice melt, says Jinlun Zhang, an oceanographer（海洋学家）at the University of Washington at Seattle.Unusually strong winds blew through the Arctic last summer. The winds pushed much of the ice out of the central Arctic,leaving a large area of thin ice and open water.Scientists also suspect that fewer clouds cover the Arctic now than in the past.Clearer skies allow more sunlight to reach the ocean.The extra heat warms both the water and the atmosphere.In parts of the Arctic Ocean last year,surface temperatures were 3.5℃warmer than average and 1.5℃warmer than the previous record high.With both air and water getting warmer,the ice is melting from both above and below. In some parts of the Beaufort Sea,north of Alaska and western Canada,ice that measured 3.3 meters thick at the beginning of the summer measured just 50 centimeters by season's end.The new measurements suggest that melting is far more severe than scientists have seen by just looking at ice covcrfrom above,says Donald K. Perovich,a geophysicist at the U.S.Army Cold Regions Researchand Engineering Laboratory in Hanover,N.H.Some scientists fear that the Arctic is stuck in a warming trend from which it may never recover.The Beaufort Sea mentioned in Paragraph 7 is an example to show_________. A:how acetirate the new measurements areB:how thick the ice is in itC:how serious the problem of the ice melt in the Arctic isD:how dangerous it is to travel to it
共用题干第一篇Arctic MeltEarth’s North and South Poles are famous for being cold and icy.Last year,however,the amnount of ice in the Arctic Ocean（北冰洋）fell to a record low.Normally,ice builds in Arctic waters around the North Pole each winter and shrinks（缩小）during the summer. But for many years,the amount of ice left by the end of summer has been declining.Since 1979,each decade has seen an 11.4 percent drop in end?of-summer ice cover. Between 1981 and 2000,ice in the Arctic lost 22 percent of its thickness,becoming I.13 meters thinner.Last summer,Arctic sea ice reached its thinnest levels yet.By the end of summer 2007,the ice had shrunk to cover just 4.2 million square kilometers.That's 38 percent less area than the average cover at that time of year. And it's a very large 23 percent below the previous record low,which was set just 2 years ago. This continuing trend has made scientists concerned.There may be several reasons for the ice melt, says Jinlun Zhang, an oceanographer（海洋学家）at the University of Washington at Seattle.Unusually strong winds blew through the Arctic last summer. The winds pushed much of the ice out of the central Arctic,leaving a large area of thin ice and open water.Scientists also suspect that fewer clouds cover the Arctic now than in the past.Clearer skies allow more sunlight to reach the ocean.The extra heat warms both the water and the atmosphere.In parts of the Arctic Ocean last year,surface temperatures were 3.5℃warmer than average and 1.5℃warmer than the previous record high.With both air and water getting warmer,the ice is melting from both above and below. In some parts of the Beaufort Sea,north of Alaska and western Canada,ice that measured 3.3 meters thick at the beginning of the summer measured just 50 centimeters by season's end.The new measurements suggest that melting is far more severe than scientists have seen by just looking at ice covcrfrom above,says Donald K. Perovich,a geophysicist at the U.S.Army Cold Regions Researchand Engineering Laboratory in Hanover,N.H.Some scientists fear that the Arctic is stuck in a warming trend from which it may never recover.What are the reasons for the ice melting according to the scientists?A:Strong winds and clear skits.B:Longer summers and shorter winters.C:Open water and thin ice.D:Heavy clouds and light winds.
共用题干第一篇Arctic MeltEarth’s North and South Poles are famous for being cold and icy.Last year,however,the amnount of ice in the Arctic Ocean（北冰洋）fell to a record low.Normally,ice builds in Arctic waters around the North Pole each winter and shrinks（缩小）during the summer. But for many years,the amount of ice left by the end of summer has been declining.Since 1979,each decade has seen an 11.4 percent drop in end?of-summer ice cover. Between 1981 and 2000,ice in the Arctic lost 22 percent of its thickness,becoming I.13 meters thinner.Last summer,Arctic sea ice reached its thinnest levels yet.By the end of summer 2007,the ice had shrunk to cover just 4.2 million square kilometers.That's 38 percent less area than the average cover at that time of year. And it's a very large 23 percent below the previous record low,which was set just 2 years ago. This continuing trend has made scientists concerned.There may be several reasons for the ice melt, says Jinlun Zhang, an oceanographer（海洋学家）at the University of Washington at Seattle.Unusually strong winds blew through the Arctic last summer. The winds pushed much of the ice out of the central Arctic,leaving a large area of thin ice and open water.Scientists also suspect that fewer clouds cover the Arctic now than in the past.Clearer skies allow more sunlight to reach the ocean.The extra heat warms both the water and the atmosphere.In parts of the Arctic Ocean last year,surface temperatures were 3.5℃warmer than average and 1.5℃warmer than the previous record high.With both air and water getting warmer,the ice is melting from both above and below. In some parts of the Beaufort Sea,north of Alaska and western Canada,ice that measured 3.3 meters thick at the beginning of the summer measured just 50 centimeters by season's end.The new measurements suggest that melting is far more severe than scientists have seen by just looking at ice covcrfrom above,says Donald K. Perovich,a geophysicist at the U.S.Army Cold Regions Researchand Engineering Laboratory in Hanover,N.H.Some scientists fear that the Arctic is stuck in a warming trend from which it may never recover.Which of the following is closest in meaning to the word"build"in the first sentence of thesecond paragraph?A:Construct.B:Establish.C:Create.D:Expand.
共用题干New research from NASA scientists suggests emissions of black soot after the way sunlight re- flects off snow.According to a computer simulation,black soot may be responsible for 25 percent of observed global warming over the past century. Soot in the higher latitudes（维度）of the Earth,where ice is more common , absorbs more of the sun's energy and warmth than an icy,white background. Dark-colored black carbon,or soot, absorbs sunlight,while lighter colored ice reflects sunlight.Soot in areas with snow and ice may play an important role in climate change.Also,if snow and ice covered areas begin melting,the warming effect increase,as the soot becomes more con-centrated on the snow surface.“This provides a positive feedback,as glaciers and ice sheets melt, they tend to get even dirtier.”said Dr. James Hansen,a researcher at NASA's Goddard Institute for Space Studies,New York.Hansen found soot's effect on snow albedo（反照率）,which may be contributing to trends to-ward early springs in the Northern Hemisphere,such as thinning Arctic sea ice and melting glac-iers permafrost. Soot also is believed to play a role in changes in the atmosphere above the oceans and land.“Black carbon reduces the amount of energy reflected by snow back into space,thus heating the snow surface more than if there were no black carbon,”Hansen said. Soot's increased absorp-tion of solar energy is especially effective in warming the world's climate.“ This forcing is unusual-ly effective,causing twice as much global warming as a carbon-dioxide forcing of the same magni-tude.”Hansen noted.Hansen cautioned,although the role of soot in altering global climate is substantial,it does not alter the fact that greenhouse gases are the primary cause of climate warming during the past century .Such gases are expected to be the largest climate forcing for the rest of the century.The researchers found that observed warming in the Northern Hemisphere was large in the winter and spring at middle and high latitudes. These observations were coherent with the researchers' climate model situations,which showed some of the largest warming effects occurred when there were heavy snow cover and sufficient sunlight. Which of the following areas shows a greater warming effect?A: Ice sea areas.B: Areas with black carbon.C: Areas covered with white snow.D: Melting glaciers.
单选题Multi-year ice is the hardest sea ice and should be avoided if possible. It is recognizable because of what tone to its surface color? （）AGreenishBBluishCGreyDGrey-white
单选题When operating in an area where sea ice and icebergs are present，which statement is TRUE? （）AIcebergs may travel in a direction many degrees different from the sea iceBBoth icebergs and sea ice will move in approximately the same direction and at the same speedCIcebergs and sea ice will move in the same direction，but at different speeds due to the sail effect of the bergDIcebergs and sea ice will move in the same direction，but the iceberg will move slower because of its underwater bulk
单选题The Atlantic hydrographic chart is being （） continuously; even as we speak submarines are charting the Arctic basin under the ice.ArehearsedBrevisedCrenewedDretiled
单选题In many areas atoll clouds (clouds of vertical development) are produced over small islands. These are the result of（）.Arising air currents produced by the warm islandsBwarm air from the sea rising over higher land areasCcool land air mixing with warm sea airDdescending air over the islands
单选题Where do polar bears usually hunt seals?AOn land.BIn open water.CIn openings in the sea ice.DAt the bottom of the sea.
单选题A team of scientists reported dramatic changes in the pattern of ice distribution in the Arctic, and a second team reported a still controversial claim.AcontentiousBsolitary. Csuperficial Dpeculiar