单选题Why does land become desert after all trees are cut down?A Because nothing remains on land except floods.B Because there are no longer trees to keep the rain and protect the top-soil.C Because too much rain sinks in and washes away the top-soil.D Becau
题目
Because nothing remains on land except floods.
Because there are no longer trees to keep the rain and protect the top-soil.
Because too much rain sinks in and washes away the top-soil.
Because roots of the trees break up the soil.
相似考题
更多“单选题Why does land become desert after all trees are cut down?A Because nothing remains on land except floods.B Because there are no longer trees to keep the rain and protect the top-soil.C Because too much rain sinks in and washes away the top-soil.D Becau”相关问题
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第1题：
Which the following statements is TRUE according to the passage?
A. The United Nations says about 50 million acres of rain forests are cut down every year.
B. Luckily people and the mass media all paid special attention to the depletion of rain forests.
C. The author thought the oceans' survival is questionable.
D. People have stopped cutting down rain forests because of the opposition of most people.
正确答案：B此题为三误一正的细节题。见第二段的第一句Unlike some environmental issues，rain forests’depletion has fortunately received significant public and media attention。
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第2题：
The streets are very wet because there was a ( ) rain last night.A、thick
B、strong
C、deep
D、heavy
参考答案：D
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第3题：
In“If it were not for the rain, the crops would become withered.”the underlined part means closest to“____”.A.Without the rain
B.Because of the rain
C.Since the rain
D.Despite the rain
答案：A
解析：题干句意为：在句子“如果不是因为这场雨，庄稼就会枯萎。”中划线部分的意思最接近（）。A选项表示“没有这场雨的话”，B、C选项都表示“因为这场雨”，C选项despite意为“尽管”，所以答案选A，“没有这场雨的话，庄稼就会枯萎。”，与题干句子意思相同。
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第4题：
A
Why do plants grow in some places and not in others? Why does some land have so much growing on it，while other land has almost no plants growing on it at all?
To grow plants need several things． One is warmth． In very cold places almost nothing grows． Plants also need water． In very dry parts of the earth only a few unusual plants can grow． That's why dry deserts everywhere are almost not covered by trees or grass．
Plants must also have a place in which to f，ut down their roots and grow． They find it diffi-culr to grow on hard land． The town is built on hard land． The plants here have only the soil found between the cracks of the stones Io grow in．
Another thing plants must have before they can grow is food．
Whar will happen if we try to make things grow on the sandy beach? A few plants，such as beach grass，will grow in sand，L ut most plants won-t． Even if the weather is warm enough．and we water the plants each day． Many of them will die because the sand on this beach has al-most no food for plants．
( )21． According to the passage，plants need _________ things to grow well．
A． two
B． three
C． four
D． five
正确答案：C
Ⅲ．21．C【解析】通读全文可知：植物的生长需要4个条件：1．适宜的温度；2．水;3．合适的土壤；4.养分。 -
第5题：
29． Why are green plants and grass helpful?
A． Because they can hold the water．
B． Because they can stop the wind from blowing the earth away．
C． Because they can keep the earth wet．
D．All the above．
正确答案：D
29.D【解析】从第二段可知A、B、C三项内容全都包括，故选D。 -
第6题：
共用题干
The world has got rainforests which cover 7% of the earth's surface.They grow around the earth's equator in South America,Central America,Africa,Southeast Asia,and Australia. Rainforests are important.(46)______.These rainforests are wet and warm.They get more than two meters of rain each year,and temperatures are usually between 24℃and 27℃．(47)______. Each area has a different environment with different plants,trees and animals.
(48)______.Every day a part of the rainforest,the same size as a football field,is destroyed because of human activities.(49)______,people cut down trees to make plantations to grow food,to get minerals or metals out of the ground or to build more and more houses.(50) ______.Cutting down trees must be prohibited and wild animals must be protected.If people break these rules,they must be arrested and severely punished._________（47）
A:Therefore strict measures must be taken
B:They give the earth oxygen,and are the home for half of the world's animals and plants
C:Because of a growing population
D:Unfortunately,these rainforests are in danger
E:Tropical rainforests are home to tribal peoples who rely on their surroundings for food,shelter,and medicines
F: They are divided into four different areas答案：F解析：本题考查的是对上下文之间意义关系的理解和对文章细节的把握。根据上文内容此处应填写的是“它们给地球提供氧气，是世界上一半动植物的家园”。
本题考查的是对上下文之间意义关系的理解。根据下文此处内容是“雨林被分成不同的区域”。
本题考查的是对上下文之间意义关系的理解。根据下文内容这里应是 “不幸的是，这些雨林处于危险之中”。
本题考查的是对上下文之间意义关系的理解。根据下文内容，此处是“由于人口增加”。
本题考查的是对上下文之间意义关系的理解。根据上下文内容，此处是 “因此，必须采取严格的措施”。 -
第7题：
共用题干
Plants in Desert
Only special plants can survive the terrible climate of a desert,for these are regions where the annual range of the soil temperature can be over 75℃．Furthermore,during the summer there are few clouds in the sky to protect plants from the sun's ray.Another problem is the fact that there are frequently strong winds that drive small,sharp particles of sand into the plants,tearing and damaging them.The most difficult problem for all forms of plant life,however,is the fact that the entire annual rainfall occurs during a few days or weeks in spring. Grasses and flowers in desert survive from one year to the next by existing through the long,hot,dry season in the form of seeds.These seeds remain inactive unless the right amount of rain falls.If no rain falls,or if insufficient rain falls,they wait until the next year,or even still the next.Another factor that helps these plants to survive is the fact that their life cycles are short.By the time the water from the spring rains disappears-just a few weeks after it falls-such plants no longer need any.
The perennials（多年生植物）have special features that enable them to survive as plants for several years.Thus,nearly all desert perennials have extensive root systems below ground and a small shoot system above ground.The large root network enables the plant to absorb as much water as possible in short time. The small shoot system,on the other hand,considerably limits water ioss by evaporation（蒸发）.
Another feature of many perennials is that after the rainy season they lose their leaves in preparation for the long,dry season,just as trees in wetter climates lose theirs in preparation for the winter.This reduces their water loss by evaporation during the dry season.Then,in next rainy season,they come fully alive once more,and grow new branches,leaves and flowers,just as the grasses and flowers in desert do.Ordinary plants are unable to survive in the desert mainly because of the changeable weather.
A:Right
B:Wrong
C:Not mentioned答案：B解析：根据第一段第一句可知，只有特殊的植物才能在沙漠中存活，这是因为沙漠中土壤的温度过高，每年的温度能达到75℃以上，而并不是因为沙漠中的气候变化多端。
根据线索词“Grasses and flowers”和“see1seects"，可以很快把第二段第一句确定为答案相关句。这个句子的大意是：沙漠里的花草年复一年以种子的形式度过漫长、炎热，而又干燥的季节。可见题干的说法与原文的说法一致，所以选择A项。
题干的大意是：沙漠里春季的雨水很快会消失，而沙漠里生命周期短的花草能够适应这一环境特点。利用题干中的“life cycles”作为线索词，可以很快把第二段第四、五句确定为答案相关句，这两句话表明，生命周期短能帮助植物在沙漠中存活，因为春季的雨水消失后，这些植物将不再需要雨水。可见题干的说法与原文的说法一致。
本篇文章并未提到冬天里花草最难生存，所以选择C项。
利用题干中的“The shoot system”作为线索词，可以把第三段最后一句确定为答案相关句。这句话表明，茎轴系统极大地限制了蒸发所造成的水分损失，而不是说茎轴系统能减少植物对太阳光线的吸收。可见题干与原文的说法不符。
倒数第二段的主题句是第一句，讲述的主要是沙漠多年生植物能生存的原因。题干表述正确，所以选择A项。
根据题干中的线索词“1ose t 1ir 1iose tneir ieaves"，不难把最后一段第一、二句确定为答案相关句。这两句话表明，沙漠多年生植物和较湿润地区的树木落叶的原因是一样的，都是为了减少水分的蒸发。题干与原文表述不符，所以选择B项。 -
第8题：
共用题干
Why Buy Shade-Grown Coffee?
When people argue about whether coffee is good for health,they're usually thinking of the health of the coffee drinker. Is it good for your heart?Does it increase blood pressure?Does it help you concentrate?However,coffee affects the health of the human population in other ways, too.
Traditionally, coffee bushes were planted under the canopy（树冠）of taller indigenous（土生土长的）trees. However, more and more farmers in Latin America are deforesting the land to grow full-sun coffees.At first,this increases production because more coffee bushes can be plan-ted if there aren't any trees.With increased production come increased profits.
Unfortunately,deforesting for coffee production immediately decreases local wildlife habitat. Native birds nest and hide from predators（捕食者）in the tall trees and migrating birds rest there.
Furthermore,in the long term,the full-sun method also damages the ecosystem because more chemical fertilizers and pesticides are needed to grow the coffee.The fertilizers and pesti- cides kill insects that eat coffee plant,but then the birds eat the poisoned insects and also die. The chemicals kill or sicken other animals as well, and can even enter the water that people will eventually drink.
Fortunately,farmers in Central and South America are beginning to grow more coffee bushes in the shade .We can support these farmers by buying coffee with such labels as"shade grown" and"bird friendly."Sure,these varieties might cost a little more.But we're paying for the health of the birds,the land,ourselves,and the planet. I think it's worth it.The full-sun method may affect the following EXCEPT______.
A: insects
B: air
C: birds
D: humans答案：B解析：主旨大意题。文章首段提出咖啡对人类健康的影响，紧接着三段讲述全日照咖啡对生态环境的破坏，最后一段讲述美国中部和南部的农民在树荫下种植咖啡，引出文章主旨，并鼓励人们买这种咖啡。因此本题选D。
文章由传统（traditionally）种植咖啡的方法（full-sun method）发展到现在种植咖啡的方法（shade-grown)，显而易见，traditionally是用来展示咖啡种植的变化。
由文章第二段中的“At first, this increases production... With increased production come increased profits.”可知，全日照咖啡的增产带来了更高的利润。故本题选D。
根据第二段中的“However, more and more farmers in Latin America are deforesting the land to grow full-sun coffees.”可知，农民们通过砍伐森林来获得更多的土地。
文章第四段提到了全日照咖啡种植的影响，包括对昆虫，鸟，其他动物，水，甚至人类的影响，但并没有提到对空气的影响。因此选择B。 -
第9题：
Why is the southern area of the Northern Territory called the Red Centre of Australia?（）
- A、Because Uluru is located there.
- B、Because it is extremely hot and dry.
- C、Because it consists of miles and miles of red-sand desert and mountain ranges.
- D、Because it lies in the tropics.
正确答案:C -
第10题：
单选题Tamarins lost the paradise of their tree-bound niche mainly because the Portuguese __________.Acut down trees to make rooms of the houses
Bcleared the forests to set up cities and farms
Cdeforested some regions for playgrounds
Dhunted the most distinctive monkeys
正确答案： B解析：
本题是细节题。第三段第一句讲到：不幸的是，葡萄牙人抵达巴西后开始清除森林以便能够腾出空地修建里约热内卢（巴西的城市）、定居地和农田，绢毛猴赖以生存的生活环境就开始消失了。(Unhappily for the lion tamarins，their tree-bound niche began to disappear after the Portuguese landed in Brazil and began clearing forest to make room for Rio de Janeiro，the settlements and farms.)，因此答案为B。 -
第11题：
单选题Trees become unhealthy if the gardener _____.Aallows too many branches to grow in the middle
Bdoes not protect them from wind
Cforces them to grow too quickly
Ddamages some of the small side branches
正确答案： D解析：
第二段最后一句“The health of a tree may be encouraged by removing branches that are blocking up the centre”说明，剪去阻塞树木中央空间的枝条可使树木健康生长，相反，保留这些枝条则会导致树木长得不健康。 -
第12题：
填空题Why should people keep the ticket after boarding the train?Because they will ____ when they leave.正确答案： need it again解析：
细节题。根据第二段第二句“Wait for the ticket to reappear and put it away safely: you’ll need it again”，等待车票重新出现并且要保管好，因为你还会再需要它的。此处应该填写need it again。 -
第13题：
23． Why does Philip like action movies?
A． Because they are scary．
B． Because they are interesting．
C． Because they are exciting．
D． Because they are boring，
正确答案：C
23．C【解析】第六句可说明这一点。 -
第14题：
I don't like the desk because it takes ( ) too much space.
A. up
B. in
C. on
D. away
正确答案：A -
第15题：
Why do you think they had not a backup computer?
A. Because it was easy down.
B. Because it was very expensive.
C. Because it was not advanced enough.
D. Because it was not as big as the main computer.
正确答案：B38．答案为B 根据各选项的比较及逻辑推断，没有备用电脑可能是经费问题，得出此题的答案为B。
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第16题：
B
Scientists are trying to make the deserts into good land again． They want to，bring water to the deserts． But more and more places of the earth is becoming deserts all the time， Scientists may not be able to change the deserts． Scientists think that people make deserts． People are do-ing bad things to the earth．
Some places on the earth don-t get very much rain． But they still don-t become deserts．This is because some green plants are growing there． Small green plants and grass are very helpful to dry places． Plants don't let the wind blow the earth away． When 8 little bit of rain falls，the plants hold the water． Without plants，the land can become a desert much more easily．
( )26． Why can the land become a desert?
A． Because some places don't get very much rain．
B． Because plants don-t let the hot sun make the earth even drier．
C． Because people don't keep the earth well．
D． Because scientists haven-t learnt enough about the deserts．
正确答案：C
26.C【解析】文章第一段提供的信息表明良田变成了沙漠是人为的。故此题选C。 -
第17题：
Why does common man in England seem to be as accurate-or as inaccurate-as the weatherman in his prediction?
A．Because the weather in English is SO variable．
B．Because the common man in England has as much knowledge about weatheras the weatherman．
C．Because by lunch time there could be thunder and lightening in England
D．Because English weather always defies forecast
正确答案：A
见文章第三自然段最后一句，即可知答案。 -
第18题：
Deforestation and Desertification(沙漠化)
The Sahel zone lies between the Sahara desert and the fertile savannahs(热带大草原)of northern Nigeria and South Sudan. The word sahel comes from Arabic and means marginal or transitional ,and this is a good description of the semi-arid(半干旱) lands, which occupy much of the Western African countries of Mail, Mauritania, Niger ,and Chad.
Unfortunately, over the last century the Sahara desert has steadily crept southwards eating into once productive Sahel lands. United Nations surveys show that over 70 percent of the dry land in agriculture use in Africa has deteriorate dover the last 30 years. Droughts have become more severe, the most recent lasting over twenty years in parts of the Sahel region. The same process of desertification is taking place across southern Africa as the Kalahari desert advances into Botswana and parts of South Africa.
One of the major causes of this desert advance is poor agricultural land use, driven by the pressures of increasing population. Overgrazing一 keeping too many farm animals on the land一means that grasses and other plants cannot recover, and scarce water supplies are exhausted. Over cultivation一 trying to grow too many crops on poor land一 results in the soil becoming even less fertile and drier, and beginning to break up. Soil erosion (侵蚀) follows, and the land turns into desert.
Another cause of desertification is loss of tree cover. Trees are cut down for use as fuel and to clear land for agricultural use. Tree roots help to bind the soil together, to conserve moisture, and to provide a habitat for her plants and animals. When trees are cut down, the soil begins to dry and loosen, wind and rain erosion increase, other plant species die, and eventually the fertile top soil may be almost entirely lost, leaving only bare rock and dust.
The effects of loss of topsoil and increased drought are irreversible. They are, however, preventable. Careful conservation of tree cover and sustainable agricultural land use have been shown to halt deterioration of soils and lessen the effects of shortage of rainfall. One project in Kita in south-west Malifunded by UNDP has involved local communities in sustainable management offorest, while at the same time providing a viable(有活力的)agricultural economy. This may be a model for similar projects in other West African countries.
文章{1~5)
The Sahel zone is an area which _____.A.is covered with sad and grass
B.has a long history
C.occupies much of South Nigeria
D.belongs to Sudan答案：A解析： -
第19题：
共用题干
Plants in Desert
Only special plants can survive the terrible climate of a desert,for these are regions where the annual range of the soil temperature can be over 75℃．Furthermore,during the summer there are few clouds in the sky to protect plants from the sun's ray.Another problem is the fact that there are frequently strong winds that drive small,sharp particles of sand into the plants,tearing and damaging them.The most difficult problem for all forms of plant life,however,is the fact that the entire annual rainfall occurs during a few days or weeks in spring. Grasses and flowers in desert survive from one year to the next by existing through the long,hot,dry season in the form of seeds.These seeds remain inactive unless the right amount of rain falls.If no rain falls,or if insufficient rain falls,they wait until the next year,or even still the next.Another factor that helps these plants to survive is the fact that their life cycles are short.By the time the water from the spring rains disappears-just a few weeks after it falls-such plants no longer need any.
The perennials（多年生植物）have special features that enable them to survive as plants for several years.Thus,nearly all desert perennials have extensive root systems below ground and a small shoot system above ground.The large root network enables the plant to absorb as much water as possible in short time. The small shoot system,on the other hand,considerably limits water ioss by evaporation（蒸发）.
Another feature of many perennials is that after the rainy season they lose their leaves in preparation for the long,dry season,just as trees in wetter climates lose theirs in preparation for the winter.This reduces their water loss by evaporation during the dry season.Then,in next rainy season,they come fully alive once more,and grow new branches,leaves and flowers,just as the grasses and flowers in desert do.Desert perennials lose their leaves after the rainy season just as trees in wetter climates lose theirs because winter arrives,but the reasons for this feature are different.
A:Right
B:Wrong
C:Not mentioned答案：B解析：根据第一段第一句可知，只有特殊的植物才能在沙漠中存活，这是因为沙漠中土壤的温度过高，每年的温度能达到75℃以上，而并不是因为沙漠中的气候变化多端。
根据线索词“Grasses and flowers”和“see1seects"，可以很快把第二段第一句确定为答案相关句。这个句子的大意是：沙漠里的花草年复一年以种子的形式度过漫长、炎热，而又干燥的季节。可见题干的说法与原文的说法一致，所以选择A项。
题干的大意是：沙漠里春季的雨水很快会消失，而沙漠里生命周期短的花草能够适应这一环境特点。利用题干中的“life cycles”作为线索词，可以很快把第二段第四、五句确定为答案相关句，这两句话表明，生命周期短能帮助植物在沙漠中存活，因为春季的雨水消失后，这些植物将不再需要雨水。可见题干的说法与原文的说法一致。
本篇文章并未提到冬天里花草最难生存，所以选择C项。
利用题干中的“The shoot system”作为线索词，可以把第三段最后一句确定为答案相关句。这句话表明，茎轴系统极大地限制了蒸发所造成的水分损失，而不是说茎轴系统能减少植物对太阳光线的吸收。可见题干与原文的说法不符。
倒数第二段的主题句是第一句，讲述的主要是沙漠多年生植物能生存的原因。题干表述正确，所以选择A项。
根据题干中的线索词“1ose t 1ir 1iose tneir ieaves"，不难把最后一段第一、二句确定为答案相关句。这两句话表明，沙漠多年生植物和较湿润地区的树木落叶的原因是一样的，都是为了减少水分的蒸发。题干与原文表述不符，所以选择B项。 -
第20题：
共用题干
Why Buy Shade-Grown Coffee?
When people argue about whether coffee is good for health,they're usually thinking of the health of the coffee drinker. Is it good for your heart?Does it increase blood pressure?Does it help you concentrate?However,coffee affects the health of the human population in other ways, too.
Traditionally, coffee bushes were planted under the canopy（树冠）of taller indigenous（土生土长的）trees. However, more and more farmers in Latin America are deforesting the land to grow full-sun coffees.At first,this increases production because more coffee bushes can be plan-ted if there aren't any trees.With increased production come increased profits.
Unfortunately,deforesting for coffee production immediately decreases local wildlife habitat. Native birds nest and hide from predators（捕食者）in the tall trees and migrating birds rest there.
Furthermore,in the long term,the full-sun method also damages the ecosystem because more chemical fertilizers and pesticides are needed to grow the coffee.The fertilizers and pesti- cides kill insects that eat coffee plant,but then the birds eat the poisoned insects and also die. The chemicals kill or sicken other animals as well, and can even enter the water that people will eventually drink.
Fortunately,farmers in Central and South America are beginning to grow more coffee bushes in the shade .We can support these farmers by buying coffee with such labels as"shade grown" and"bird friendly."Sure,these varieties might cost a little more.But we're paying for the health of the birds,the land,ourselves,and the planet. I think it's worth it.How do farmers find more land for growing full-sun coffee?
A: They buy more land from other farmers.
B: They cut down trees.
C: They move to another country.
D: They turn grassland into farmland.答案：B解析：主旨大意题。文章首段提出咖啡对人类健康的影响，紧接着三段讲述全日照咖啡对生态环境的破坏，最后一段讲述美国中部和南部的农民在树荫下种植咖啡，引出文章主旨，并鼓励人们买这种咖啡。因此本题选D。
文章由传统（traditionally）种植咖啡的方法（full-sun method）发展到现在种植咖啡的方法（shade-grown)，显而易见，traditionally是用来展示咖啡种植的变化。
由文章第二段中的“At first, this increases production... With increased production come increased profits.”可知，全日照咖啡的增产带来了更高的利润。故本题选D。
根据第二段中的“However, more and more farmers in Latin America are deforesting the land to grow full-sun coffees.”可知，农民们通过砍伐森林来获得更多的土地。
文章第四段提到了全日照咖啡种植的影响，包括对昆虫，鸟，其他动物，水，甚至人类的影响，但并没有提到对空气的影响。因此选择B。 -
第21题：
Why has Australia always been a continent with few people?（）
- A、Because Australia is too far away from Europe.
- B、Because Australia is the least mountainous and most level of the world.s continents.
- C、Because Australia is separated from the rest of the world by seas.
- D、Because most of the continent is hot and dry.
正确答案:D -
第22题：
单选题Why do forests in many parts of the world slowly disappear?ANew trees are not looked after properly.
BMany trees have been cut down by man.
CMan has not paid enough attention to planting trees.
DAll of the above.
正确答案： C解析：
细节题。第二段列举了森林减少的原因。 -
第23题：
单选题Countries sometimes spoil their beauty spots because ______.Athey are too poor to build beautiful hotels on them
Bthey have to cut down trees to build hotels on them
Cthey have to sell them to borrow money from foreign banks
Dthey are lacking experience in building hotels
正确答案： A解析：
录音中提到“What they spend on building has to be borrowed produces only chains of ugly hotels wherever there are beauty spots supposed to attract tourists”，意思是：他们(指前面提到的一些贫穷的国家)需要借钱来盖旅馆，可结果却是丑陋的旅馆横亘在风景优美的景区，而这些景区本应该吸引游客前来赏景的。由此可以推断出，这些国家毁了他们的风景区只是因为他们太穷不能建造美丽的旅馆，所以A项为正确答案。