The main idea for this passage is A)Our future world will be very different from today' s world. B)Farmwork will be largely automated and computerized in the future C)There will be more office jobs and fewer factory jobs in the furure D)New technology will create many new jobs and professions and will make many old ones outdate Passage 5 We' ve been hearing about the greenhouse effect for years. Now, two U. S reports predict that it may happen sooner than we counted on. Released separately by the U.S. Environmental Protection Agency(EPA)and the National Research Council(NRC), the reports warn that the first effects may felt as early as the 1990s. a greenhouse can produce a tropical climate in sub zero weather by trapping the suns rays under glass. Scientists say we re creating the same effect on a global scale by burning fossil fuels(coal, oil, gas). Carbon dioxide is a by product of the burning. The gas allows sunlight to penetrate the atmosphere but slows the escape of heat back into space. This one way trip for the sun's rays tends to make our planet a big greenhouse. We are beginning to warm up, just like a pot of violets under gla We ve been burning fossil fuels for centuries. However the automobile and heavy industry have speeded up the release of carbon dioxide so much that experts say it' s almost too late to prevent the coming results. Even a switch to other forms of energy might do no more than de lay change A warming trend in climate will be the main effect. At first, that seems all to the good, especially for Canadians. But a closer look reveals dangers which may call for ma jor adjustments all over the world. Average temperatures may rise by 2c by the year 2040, and by 5c by 2100. Increases up to three times as large may take place at the poles, however, causing the ice caps to melt rapidly. The oceans would then rise, causing flooding of coastal cities such as Halifax To compensate a little, Halifax could have a climate like Daytona Beach, Florida, by 2100. Coastal cities will have to plan for coming changes. The loss of land, houses, and factories can be reduced by planning new building sites, erecting sea walls, and contouring(循等高线修筑)the land. Even so, low lying countries will suffer. One third of the Netherlands, Florida and ouisiana, and large parts of Bangladesh will be submerged. Many port cities will look like Venice. he warmer climate will bring changed patterns of drought and rainfall. The desert Sahel area of Africa will get more rain, but the wheat growing areas of the United States, the Soviet Union, and China will be drier and less productive. More carbon dioxide will likely spur plant growth, but me regions may become too hot and dry for crops Earth has gone through temperature swings before, but only slowly over thousands of years. The coming changes may take place in a mere 120 years, and the NrC report says they would have"few or no precedents in the Earths recent history. It is the global environment issue of the century ", says Henry Hengeveld of Environment Canada. For the first time man will change his environment on a global basis. Others like Jack Vallentyne, a senior Canadian water scientist, rank the greenhouse effect with nuclear war and the population explosion in terms of its potential impact on humans. In Canada, as elsewhere, some will gain and some lose from the greenhouse effect. The NRC report stresses that we need to learn a good deal more about the degree of temperature change, the timing, and the consequences before we jump in with costly plans which may turn out wrong In the first paragraph, the phrase "counted on"means A)hoped B)wished C D)accounted The "Greenhouse effect" is so called because A)fossil fuels are burnt in green houses B)a carbon dioxide is causing the Earth to warm up C)the worlds climate has become tropical by the penetration of the sunlight D)the sun's rays are trapped by the glass in the greenhouseThe main idea for this passage is: A)Our future world will be very different from today′s world. B)Farmwork will be largely automated and computerized in the future. C)There will be more office jobs and fewer factory jobs in the furure. D)New technology will create many new jobs and professions and will make many old ones outdated. Passage 5 We′ve been hearing about the greenhouse effect for years.Now,two U.S.reports predict that it may happen sooner than we counted on.Released separately by the U.S.Environmental Protection Agency(EPA)and the National Research Council(NRC),the reports warn that the first effects may be felt as early as the 1990s. A greenhouse can produce a tropical climate in sub zero weather by trapping the sun′s rays under glass.Scientists say we′re creating the same effect on a global scale by burning fossil fuels(coal,oil, gas).Carbon dioxide is a by product of the burning.The gas allows sunlight to penetrate the atmosphere but slows the escape of heat back into space.This one way trip for the sun′s rays tends to make our planet a big greenhouse.We are beginning to warm up,just like a pot of violets under glass. We′ve been burning fossil fuels for centuries.However ,the automobile and heavy industry have speeded up the release of carbon dioxide so much that experts say it′s almost too late to prevent the coming results.Even a switch to other forms of energy might do no more than delay changes for a few years. A warming trend in climate will be the main effect.At first,that seems all to the good,especially for Canadians.But a closer look reveals dangers which may call for major adjustments all over the world.Average temperatures may rise by 2℃ by the year 2040,and by 5 ℃ by 2100.Increases up to three times as large may take place at the poles,however,causing the ice caps to melt rapidly.The oceans would then rise,causing flooding of coastal cities such as Halifax.To compensate a little,Halifax could have a climate like Daytona Beach,Florida,by 2100. Coastal cities will have to plan for coming changes.The loss of land,houses,and factories can be reduced by planning new building sites,erecting sea walls,and contouring(循等高线修筑)the land.Even so ,low lying countries will suffer.One third of the Netherlands,Florida and Louisiana,and large parts of Bangladesh will be submerged.Many port cities will look like Venice. The warmer climate will bring changed patterns of drought and rainfall.The desert Sahel area of Africa will get more rain,but the wheat growing areas of the United States,the Soviet Union,and China will be drier and less productive.More carbon dioxide will likely spur plant growth,but some regions may become too hot and dry for crops. Earth has gone through temperature swings before,but only slowly over thousands of years.The coming changes may take place in a mere 120 years,and the NRC report says they would have“few or no precedents in the Earth′s recent history.” “It is the global environment issue of the century”,says Henry Hengeveld of Environment Canada. “For the first time man will change his environment on a global basis.”Others like Jack Vallentyne,a senior Canadian water scientist,rank the greenhouse effect with nuclear war and the population explosion in terms of its potential impact on humans. In Canada,as elsewhere,some will gain and some lose from the greenhouse effect.The NRC report stresses that we need to learn a good deal more about the degree of temperature change,the timing,and the consequences before we jump in with costly plans which may turn out wrong. In the first paragraph,the phrase“counted on” means _____ . A)hoped B)wished C)expected D)accounted The“Greenhouse effect”is so called because _____ . A)fossil fuels are burnt in green houses B)a carbon dioxide is causing the Earth to warm up C)the world′s climate has become tropical by the penetration of the sunlight D)the sun′s rays are trapped by the glass in the greenhouse