AWhy 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． Pla
题目
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
相似考题
更多“AWhy do plants grow in some places and not in others? Why does some land have so much grow ”相关问题
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第1题：
25． Why do we call the sun"a life-giving star"?
A． Because it gives us warmth．
B． Because there are some living things on it．
C． Because plants and animals can't live without it．
D． Because people have to live in the dark without it．
正确答案：C
z5.C【解析】由最后一段中“The' sun gives us...1t makes life possible on our earth.”可知。 -
第2题：
A
In China，more and more middle school students are getting shorter sleeping time than be-fore． Most students sleep less than nine hours every night，because they have much homework to do. Some homework is given by their teachers，and some by their parents． Also，some students don't know how to save time .They are not careful enough while they do their homework，so it takes them a Iot of time． Some students spend too much time watching TV or playing computer games．They stay up very late． Some students have to get up early every morning on weekdays to get to school on time by bus or by bike．lt can be a long way from home to school．
Schools and parents should cut down some of the homework so that our children can enjoy more than nine hours of sleep every night for their health． For children，we should make best use of our time． When we have enough time for sleeping，we will find it much better for both our study and health．
( )21． What makes most students sleep less than nine hours every night?
A． Watching TV．
B． Playing computer games．
C． Doing their homework．
D． Doing housework．
正确答案：C
21．C【解析】由第一段第二句可知由于做作业，大多数学生睡眠少于9小时。 -
第3题：
Passage One
Animals have different ways of protecting themselves against wintertime weather. Some animals grow heavy coats of fur or feathers, while others dig into the ground to find a warm wintertime home.
Some animals spend the winter in a deep sleep because by going to sleep they avoid the time of the year when food is scarce and the temperatures are low. Their sleep is known as hibernation.
There is much about hibernation that puzzles scientists. For example, they are wondering how hibernation came into being. Some scientists have explored the possibility that animals release a chemical that starts them hibernating.
One thing that scientists are certain about is that animals hibernate only when it is cold. Hibernation is a seasonal practice.
Some animals that fall into a wintertime sleep are not true hibernators because they spend only a part of the cold season asleep. Bears, for example, can easily be awakened from their winter nap. They are not true hibernators.
Sometimes it is difficult to determine whether a particular animal is a true hibernator. For example, some mice hibernate, but others do not. The same is true of bats. Some of them hibernate. Others do not.
36. Hibernation is a seasonal practice. This means it ______.
A. takes place only during a particular season
B. occurs only during the night
C. is a daily practice
D. only happens when a species becomes over-populated
正确答案：A
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第4题：
().
I need to look for some papers to add to my research report.
A. Do you like the library in our school?
B. How many papers have you read so far?
C. Why not comfortably stay at home to log onto the Web?
参考答案：C
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第5题：
23． From the passage，we can know it is ________for plants to grow in dry places．
A． easy
B． difficult
C． impossible
D． important
正确答案：B
23.B【解析】由第二段第五句“In very dry parts of the earth only a few unusual plants can grow.”可知 B是正确答案。 -
第6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7题：
共用题干
Ecosystem
1. The word “ecosystem” is short for ecological（生态的）system. An ecosystem is where living creatures expand within a given area. You can say that an ecosystem is the natural environment where biological organisms（生物）such as plants,animals and humans co-exist in this world. So naturally that includes you and me. Yes,we are all members of an ecosystem!
2 .There are different kinds of ecosystems depending on the type of surface or environ-ment. Most are naturally made such as the ocean or lake and the desert or rainforest.Some are man-made or artificial to encourage co-habitation（同居）between living and non-living things in a monitored environment,such as a zoo or garden.
3 .Plants make up the biggest group of biological creatures within an ecosystem,and that's because they are the natural food producers for everyone. Plants raised in the earth need air and collect sunlight to help them grow. When they grow,the plants and its fruits or flowers eventually become a source of food to animals,microorganisms（微生物）and even hu- mans,of course. Food is then converted to energy for the rest of us to function,and this hap-pens in a never-ending cycle until the living creatures die and break up back in the earth.
4 .Ecosystems are the basis of survival for all living things.We depend on plants and ani-mals for food. In order for us to exist,we need to grow and care about other organisms. We also need to care for the non-living things within our environment like our air and water so we can continue living as a population. Since plants,animals and humans are all of various species（物种）,we all play a role in maintaining the ecosystem.
5 .To preserve our ecosystems,we should stop using too much energy,which happens when we consume more than our share of resources. Humans should not disturb the natural habitat（栖息地）of plants and animals,and allow them to grow healthily for the cycle to con-tinue. Too many people in a habitat can mean displacement（搬迁）: imagine being thrown out of your home because there is no more space for everyone. Worse,overpopulation can also ru- in the environment and cause destruction of existing plants and animals.Paragraph 4_________
A: What Can We Do to Help Protect Ecosystems?
B: What Are Different types of Ecosystems?
C: What Is an Ecosystem?
D: What Destroys Ecosystems?
E: How Does an Ecosystem Work?
F: Why Are Ecosystems Emportant?答案：F解析：文章第二段主要讲根据不同的表层类型和环境类型，有各种不同的生态系统。主题句之后就是介绍不同的生态系统。B项What Are Different Types of Ecosystems? （有哪些不同类型的生态系统？）符合本段主题，故选B。
文章第三段主要讲植物是生态系统中最大的群体，因为它要为所有生态系统的成员制造食物。地球上的植物需要空气和阳光的帮助才能生长，在生长过程中，植物及其果实和花朵最终变成动物、微生物和人类的食物来源，然后食物转化成能量使个体发挥功能，这个过程循环进行，直到生物死亡，在土壤中分解。E项How Does an Ecosystem Work?（生态系统如何运行？）符合本段主题，故选E。
文章第四段主要讲生态系统为所有生物提供最基本的生存模式。我们需要从动植物身上获得食物，我们也需要空气和水来继续生存。动植物和人作为不同的物种，在维持生态系统上都发挥着作用。F项Why Are Ecosystems Important?（生态系统为什么重要？）符合本段主题，故选F。
文章第五段主要讲为了保护生态系统，我们要停止过度使用能源，不应该扰乱动植物的栖息地，应该控制人口数量。A项What Can We Do to Help Protect Ecosystems?（我们能做些什么来帮助保护生态系统？）符合本段主题，故选A。
题干意为“在一个生态系统中，植物、动物和人类共同生活在一定地区。”文章第一段第三句指出，你可以说生态环境是生物，比如植物、动物、人类，共同生活的自然环境。C项a given area（一定地区）与原句意思相符，故选C。
题干意为“在一个生态系统中植物非常重要，因为对于其他生物来说，它们是食物来源。”文章第三段第一句指出，植物是生态系统中最大的群体，因为它要为所有生态系统的成员制造食物。E项the source of food（食物来源）与原句意思相符，故选E。
题干意为“植物、动物和人类在维持生态系统中都发挥作用。”文章第四段最后一句指出，植物、动物和人属于不同物种，我们在维持生态系统中都发挥作用。D项the maintenance of the ecosystem（生态系统的维持）与原句意思相符，故选D。
题干意为“为了保护我们的生态系统，我们应该只使用我们的那份资源。” 文章第五段第一句指出，为了保护生态系统，我们应该停止过度使用能源，除了我们的那份资源外不应该消耗别的资源。A项our share of resources（我们的那份资源）与原句意思相符，故选A。 -
第8题：
共用题干
“Salty” Rice Plant Boosts Harvests
British scientists are breeding a new generation of rice plants that will be able to grow in soil containing salt water. Their work may enable abandoned farms to become productive once more.
Tim Flowers and Tony Yeo,from Sussex University's School of Biological Sciences,have spent several years researching how crops,such as rice,could be made to grow in water that has become salty.
The pair have recently begun a three-year programme,funded by the Biotechnology and Biological Sciences Research Council,to establish which genes enable some plants to survive salty conditions. The aim is to breed this capability into crops,starting with rice.
It is estimated that each year more than 10m hectares（公顷）of agricultural land are lost because salt gets into the soil and stunts（妨碍生长）plants. The problem is caused by several factors. In the tropics , mangroves（红树林）that create swamps（沼泽）and traditionally formed barriers to sea water have been cut down .In the Mediterranean,a series of droughts have caused the water table to drop,allowing sea water to seep（渗透）in. In Latin America , irrigation often causes problems when water is evaporated（蒸发）by the heat , leaving salt deposits behind.
Excess salt then enters the plants and prevents them functioning normally.Heavy concentrations of minerals in the plants stop them drawing up the water they need to survive.
To overcome these problems,Flowers and Yeo decided to breed rice plants that take in very little salt and store what they do absorb in cells that do not affect the plants' growth.They have started to breed these characteristics into a new rice crop,but it will take about eight harvests before the resulting seeds are ready to be considered for commercial use.
Once the characteristics for surviving salty soil are known,Flowers and Yeo will try to breed the appropriate genes into all manners of crops and plants.Land that has been abandoned to na- ture will then be able to bloom again,providing much needed food in the poorer countries of the world.The attitude of the author towards the research project is______.
A: positive
B: negative
C: suspicious
D: indifferent答案：A解析：第二段的第一句话把两位研究人员Tim Flowers和Tony Yeo的关系讲得很清楚，他们来自同一所大学Sussex University的School of Biological Sciences，故是同事。从上下文看他们不可能是学生，更不会是种水稻的；第三段的第一句里用了pair这个词，但pair不一定就是夫妻，从他们的名字看他们不是同一个姓，而且Tim和Tony都是男性的名字。
本题的答案可以在第三段里找到，这段的第一句话说他们开始了一个为期3年的研究项目，目的是“establish which genes enable some plants to survive salty condition”（确认哪些基因使得某些作物能在含盐的条件下生长）。这和选项B是同一个意思。
引起盐分渗入土壤的3个原因都在第四段里谈到了：第一是阻档海水的天然屏障红树林被砍伐（A)；第二是在地中海地区严重的旱灾导致水平面下降，海水渗透（B); 第三是在拉丁美洲，水分被高温蒸发后留下了盐分（D）。
affect这个动词的意思是“影响”，和influence是同义词，在这个上下文里可以替换用。
四个选项的意思分另，1是：肯定的（positive)、否定的（negative)、有怀疑的（suspicious)、冷淡的（indifferent)，从全文看作者时他们的研究无疑是肯定的。 -
第9题：
共用题干
“Salty” Rice Plant Boosts Harvests
British scientists are breeding a new generation of rice plants that will be able to grow in soil containing salt water. Their work may enable abandoned farms to become productive once more.
Tim Flowers and Tony Yeo,from Sussex University's School of Biological Sciences,have spent several years researching how crops,such as rice,could be made to grow in water that has become salty.
The pair have recently begun a three-year programme,funded by the Biotechnology and Biological Sciences Research Council,to establish which genes enable some plants to survive salty conditions. The aim is to breed this capability into crops,starting with rice.
It is estimated that each year more than 10m hectares（公顷）of agricultural land are lost because salt gets into the soil and stunts（妨碍生长）plants. The problem is caused by several factors. In the tropics , mangroves（红树林）that create swamps（沼泽）and traditionally formed barriers to sea water have been cut down .In the Mediterranean,a series of droughts have caused the water table to drop,allowing sea water to seep（渗透）in. In Latin America , irrigation often causes problems when water is evaporated（蒸发）by the heat , leaving salt deposits behind.
Excess salt then enters the plants and prevents them functioning normally.Heavy concentrations of minerals in the plants stop them drawing up the water they need to survive.
To overcome these problems,Flowers and Yeo decided to breed rice plants that take in very little salt and store what they do absorb in cells that do not affect the plants' growth.They have started to breed these characteristics into a new rice crop,but it will take about eight harvests before the resulting seeds are ready to be considered for commercial use.
Once the characteristics for surviving salty soil are known,Flowers and Yeo will try to breed the appropriate genes into all manners of crops and plants.Land that has been abandoned to na- ture will then be able to bloom again,providing much needed food in the poorer countries of the world.Which of the following is NOT mentioned as a cause of the problem discussed in the passage?
A: Natural barriers to sea water have been destroyed.
B: The water table has gone down after droughts.
C: Sea level has been continuously rising.
D: Evaporation of water leaves salt behind.答案：C解析：第二段的第一句话把两位研究人员Tim Flowers和Tony Yeo的关系讲得很清楚，他们来自同一所大学Sussex University的School of Biological Sciences，故是同事。从上下文看他们不可能是学生，更不会是种水稻的；第三段的第一句里用了pair这个词，但pair不一定就是夫妻，从他们的名字看他们不是同一个姓，而且Tim和Tony都是男性的名字。
本题的答案可以在第三段里找到，这段的第一句话说他们开始了一个为期3年的研究项目，目的是“establish which genes enable some plants to survive salty condition”（确认哪些基因使得某些作物能在含盐的条件下生长）。这和选项B是同一个意思。
引起盐分渗入土壤的3个原因都在第四段里谈到了：第一是阻档海水的天然屏障红树林被砍伐（A)；第二是在地中海地区严重的旱灾导致水平面下降，海水渗透（B); 第三是在拉丁美洲，水分被高温蒸发后留下了盐分（D）。
affect这个动词的意思是“影响”，和influence是同义词，在这个上下文里可以替换用。
四个选项的意思分另，1是：肯定的（positive)、否定的（negative)、有怀疑的（suspicious)、冷淡的（indifferent)，从全文看作者时他们的研究无疑是肯定的。 -
第10题：
（）your mother（）some cleaning on Sundays?
- A、Does；does
- B、Do；does
- C、Does；do
正确答案:C -
第11题：
单选题It can be inferred from the last paragraph that the cultural activities in universities will grow if the government and individuals______.Aincrease the finance of higher education
Bcurtail some cultural activities
Copen more theaters
Dwork out some rules for donation
正确答案： A解析：
推断题。文章最后一段提到“the resulting cutbacks in state aid and private donations placed a strain on the financing of higher education that curtailed the growth or sometimes even threatened the survival of many cultural program”，即“政府和个人资助的减少使得抑制甚至威胁到了大学文化艺术活动的生存”。由此推断，如果增加对最高教育的资助，那么大学的文化艺术活动就会繁荣起来，所以选A项。 -
第12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13题：
Why does author say that they were lucky in the third paragraph?
A. Because her situation was not serious.
B. Because many other places were flooded.
C. Because she had been to Northern India.
D. Because some others suffered even more.
正确答案：D
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第14题：
9．—Does Tom ________to do?
—No， he doesn’t．
A． have some homework
B． has any homework
C． have any homework
D． have any homeworks
正确答案：C
9．C【解析】Tom为第三人称单数形式，故用does 一来提问，而此时渭语动词要用原形．any用在疑问句中．homework足不可数名词，故选C。 -
第15题：
Most animals have little connection with animals of different kind, unless they hunt them for food. Sometimes, however, two kinds of animals come together in a partnership ( 伙伴关系 ) which does good to both of them. You may have noticed some birds sitting on the backs of sheep. This is not because they want a ride, but because they find easy food in the parasites (寄生虫 ) on sheep. The sheep allow the birds to do so because they remove the cause of discomfort. So although they can manage without each other, they do better together.
Sometimes an animal has a plant partner. The relationship develops until the two partners cannot manage without each other. This is so in the corals ( 珊瑚 ) of the sea. In their skins they have tiny plants act as "dustman", taking some of the waste products form. the corals and giving in return oxygen which the animal needs to breathe. If the plants are killed, or are ever prevented from lighting so that they cannot live normally, the corals will die.
1、Some birds like to sit on a sheep because ( ).
A、they can eat its parasites
B、 they depend on the sheep for existence
C、 they enjoy traveling with the sheep
D、 they find the position most comfortable
2、The underlined word "they" in the last sentence of the first paragraph refers to ( ).
A、birds and parasites
B、birds and sheep
C、parasites and sheep
D、sheep, birds and parasites
3、What does the second paragraph mainly discuss? ( )
A、Some animals and plants depend on each other for existence.
B、 Some animals and plants develop their relationship easily.
C、 Some plants depend on each other for foo
D、 Some animals live better together.
4、What does this article talk about? ( )
A、Two kinds of animals for a partnership.
B、Most animals only have connection with animals.
C、The connection between the living things.
D、Corals have some connection with plants.
正确答案：1A 2B 3A 4C
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第16题：
Why did the early Pilgrims want to share their feast with the Indians?
A. To show friendship.
B. To ask for their help in the coming winter.
C. So they could eat some Indian bread puddings.
D. To try to teach them to grow crops.
正确答案：A52．答案为A 根据第二段清教徒刚到新大陆时的经历，可知是印地安人帮助了他们，因此丰收的时候，清教徒邀请印地安人做客以表示友好和感谢。
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第17题：
24． The reason why most plants can’t grow on the sandy beach is that
A． there isn't enough sunlight
B． there is too much water
C． it is too crowded there
D． it has little food for plants
正确答案：D
24.D【解析】由文章最后一句可知沙滩里没有植物生长所需要的养分。 -
第18题：
27． Scientists ____to make the deserts into good land again．
A． carry water'
B．grow food
C． do nothing
D． study a lot
正确答案：D
27.D【解析】文章第一段表明科学家们对沙漠进行了大量的研究，故此题选D。 -
第19题：
Why do some people choose self-catering accommodation? __________A.To experience a warmer family atmosphere
B.To enrich their knowledge of English
C.To entertain friends as they like
D.To enjoy much more freedom答案：D解析：最后一段提到“This kind of accommodation offers an independent lifestyle and is moresuitable for the long-stay student．”在结合文章第一段内容可知，D项正确。 -
第20题：
共用题干
“Salty” Rice Plant Boosts Harvests
British scientists are breeding a new generation of rice plants that will be able to grow in soil containing salt water. Their work may enable abandoned farms to become productive once more.
Tim Flowers and Tony Yeo,from Sussex University's School of Biological Sciences,have spent several years researching how crops,such as rice,could be made to grow in water that has become salty.
The pair have recently begun a three-year programme,funded by the Biotechnology and Biological Sciences Research Council,to establish which genes enable some plants to survive salty conditions. The aim is to breed this capability into crops,starting with rice.
It is estimated that each year more than 10m hectares（公顷）of agricultural land are lost because salt gets into the soil and stunts（妨碍生长）plants. The problem is caused by several factors. In the tropics , mangroves（红树林）that create swamps（沼泽）and traditionally formed barriers to sea water have been cut down .In the Mediterranean,a series of droughts have caused the water table to drop,allowing sea water to seep（渗透）in. In Latin America , irrigation often causes problems when water is evaporated（蒸发）by the heat , leaving salt deposits behind.
Excess salt then enters the plants and prevents them functioning normally.Heavy concentrations of minerals in the plants stop them drawing up the water they need to survive.
To overcome these problems,Flowers and Yeo decided to breed rice plants that take in very little salt and store what they do absorb in cells that do not affect the plants' growth.They have started to breed these characteristics into a new rice crop,but it will take about eight harvests before the resulting seeds are ready to be considered for commercial use.
Once the characteristics for surviving salty soil are known,Flowers and Yeo will try to breed the appropriate genes into all manners of crops and plants.Land that has been abandoned to na- ture will then be able to bloom again,providing much needed food in the poorer countries of the world.Flowers and Yeo have started a program______.
A: to find ways to prevent water pollution
B: to identify genes that promote growth in salty soil
C: to breed rice plants that taste salty
D: to find ways to remove excessive salt from soil答案：B解析：第二段的第一句话把两位研究人员Tim Flowers和Tony Yeo的关系讲得很清楚，他们来自同一所大学Sussex University的School of Biological Sciences，故是同事。从上下文看他们不可能是学生，更不会是种水稻的；第三段的第一句里用了pair这个词，但pair不一定就是夫妻，从他们的名字看他们不是同一个姓，而且Tim和Tony都是男性的名字。
本题的答案可以在第三段里找到，这段的第一句话说他们开始了一个为期3年的研究项目，目的是“establish which genes enable some plants to survive salty condition”（确认哪些基因使得某些作物能在含盐的条件下生长）。这和选项B是同一个意思。
引起盐分渗入土壤的3个原因都在第四段里谈到了：第一是阻档海水的天然屏障红树林被砍伐（A)；第二是在地中海地区严重的旱灾导致水平面下降，海水渗透（B); 第三是在拉丁美洲，水分被高温蒸发后留下了盐分（D）。
affect这个动词的意思是“影响”，和influence是同义词，在这个上下文里可以替换用。
四个选项的意思分另，1是：肯定的（positive)、否定的（negative)、有怀疑的（suspicious)、冷淡的（indifferent)，从全文看作者时他们的研究无疑是肯定的。 -
第21题：
共用题干
“Salty” Rice Plant Boosts Harvests
British scientists are breeding a new generation of rice plants that will be able to grow in soil containing salt water. Their work may enable abandoned farms to become productive once more.
Tim Flowers and Tony Yeo,from Sussex University's School of Biological Sciences,have spent several years researching how crops,such as rice,could be made to grow in water that has become salty.
The pair have recently begun a three-year programme,funded by the Biotechnology and Biological Sciences Research Council,to establish which genes enable some plants to survive salty conditions. The aim is to breed this capability into crops,starting with rice.
It is estimated that each year more than 10m hectares（公顷）of agricultural land are lost because salt gets into the soil and stunts（妨碍生长）plants. The problem is caused by several factors. In the tropics , mangroves（红树林）that create swamps（沼泽）and traditionally formed barriers to sea water have been cut down .In the Mediterranean,a series of droughts have caused the water table to drop,allowing sea water to seep（渗透）in. In Latin America , irrigation often causes problems when water is evaporated（蒸发）by the heat , leaving salt deposits behind.
Excess salt then enters the plants and prevents them functioning normally.Heavy concentrations of minerals in the plants stop them drawing up the water they need to survive.
To overcome these problems,Flowers and Yeo decided to breed rice plants that take in very little salt and store what they do absorb in cells that do not affect the plants' growth.They have started to breed these characteristics into a new rice crop,but it will take about eight harvests before the resulting seeds are ready to be considered for commercial use.
Once the characteristics for surviving salty soil are known,Flowers and Yeo will try to breed the appropriate genes into all manners of crops and plants.Land that has been abandoned to na- ture will then be able to bloom again,providing much needed food in the poorer countries of the world.Which of the following statements about Flowers and Yeo is true?
A: They are students at Sussex University.
B: They are rice breeders.
C: They are husband and wife.
D: They are colleagues at an institution of higher learning.答案：D解析：第二段的第一句话把两位研究人员Tim Flowers和Tony Yeo的关系讲得很清楚，他们来自同一所大学Sussex University的School of Biological Sciences，故是同事。从上下文看他们不可能是学生，更不会是种水稻的；第三段的第一句里用了pair这个词，但pair不一定就是夫妻，从他们的名字看他们不是同一个姓，而且Tim和Tony都是男性的名字。
本题的答案可以在第三段里找到，这段的第一句话说他们开始了一个为期3年的研究项目，目的是“establish which genes enable some plants to survive salty condition”（确认哪些基因使得某些作物能在含盐的条件下生长）。这和选项B是同一个意思。
引起盐分渗入土壤的3个原因都在第四段里谈到了：第一是阻档海水的天然屏障红树林被砍伐（A)；第二是在地中海地区严重的旱灾导致水平面下降，海水渗透（B); 第三是在拉丁美洲，水分被高温蒸发后留下了盐分（D）。
affect这个动词的意思是“影响”，和influence是同义词，在这个上下文里可以替换用。
四个选项的意思分另，1是：肯定的（positive)、否定的（negative)、有怀疑的（suspicious)、冷淡的（indifferent)，从全文看作者时他们的研究无疑是肯定的。 -
第22题：
单选题According to some scientists, the computer will do much harm to people’s health as smoking and drugs do.Adoes much harm...smoking
Bwill do as much harm...cigarettes
Cwill do so much harm...smoking
Ddoes as much harm...cigarettes
正确答案： A解析：
同级比较，即as…as…句型。该句中will表示推测，原句中as后面连接了的两个词为并列成分，划线部分也应该用名词，即将smoking改为cigarettes。因此答案为选项B。 -
第23题：
单选题—It’s time to graduate. Why not get our teachers some flowers to say thanks?—______They have done so much for us and we will miss them.AThat’s all right
BGood idea
CI hope not
正确答案： A解析：
句意：—该庆祝庆祝了。为什么不送点花给老师们以示谢意呢？—好主意！他们为我们做了很多，我们会想念他们的。本题考查情景交际。A项意为“没关系”；B项意为“好主意”；C项意为“我不希望这样”。由题干中的建议可知，B选项为正确答案。