Bananas are one of the world’s most important food crops. They are also one of

  Bananas are one of the world’s most important food crops. They are also one of

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  Bananas are one of the world’s most important food crops. They are also one of the most valuable exports. Bananas do not grow from seeds. Instead, they grow from existing plants. Bananas are threatened by disease because all the plants on a farm are copies of each other. They all share the same genetic weaknesses. For example, the Cavendish banana is most popular in North American and European markets. However, some kinds of fungus organisms easily infect the Cavendish. Black Sigatoka disease affects the leaves of Cavendish banana plants. The disease is controlled on large farms by putting chemicals on the plants’ leaves. Farmers put anti-fungal chemicals on their crops up to once a week.

Another fungal disease is more serious. Panama disease attacks the roots of the banana plants. There is no chemical treatment for this disease. Infected plants must be destroyed. Panama disease has affected crops in Southeast Asia, Australia and South Africa. There is concern that it may spread to bananas grown in the Americas. This could threaten an important export product for Central and South America.
The International Network for the Improvement of Banana and Plantain supports research on bananas. The group has headquarters in France and other offices in the major banana-growing areas of the world. The group says that more research must be done to develop improved kinds of bananas. The group says that fungal diseases mainly affect only one kind of banana. In fact, there are five hundred different kinds of bananas. Food and Agriculture Organization of the United Nations has said that the Cavendish banana represents only 10% of world production.
The U. N. agency says farmers should grow different kinds of bananas. This protects against diseases that affect only one kind. Experts warn that disease may cause the Cavendish banana to disappear. This happened earlier to another popular banana because of its genetic weakness against disease.
小题1:What does this passage mainly tell us?
A.Bananas are the world’s most important food crops.
B.The risk to a popular banana shows need to grow other kinds.
C.There are five hundred different kinds of bananas.
D.How to grow bananas in different countries.
小题2:Bananas are threatened by disease because   .
A.they grow from seeds
B.they are one of the most valuable exports
C.the only way to prevent it is to put chemicals on their leaves
D.they have genetic weaknesses against disease
小题3: Panama disease   .
A.doesn’t belong to fungal disease
B.affects the leaves of banana plants
C.destroys bananas more seriously than Black Sigatoka disease
D.has spread to bananas all over the world
小题4: We can infer from Paragraph 3 that   .
A.the center of the group is in the US
B.the Cavendish banana covers only a small part of the yield of bananas
C.the key to solving the disease is to research all kinds of bananas
D.each fungal disease affects five hundred different kinds of bananas

答案

小题1:B
小题2:D
小题3:C
小题4:B
解析

【文章大意】香蕉由于遗传性的抗病弱点, 在不久的将来有的品种可能会消失。文章列举了两种威胁Cavendish香蕉的真菌病, 国际组织建议农民种植更多种类的香蕉。
小题1:选B。主旨大意题。根据全文内容和结构判断, 文章主要介绍威胁Cavendish香蕉的真菌类疾病, 进而显示出种植其他种类香蕉的必要性。故答案为B。
小题2:选D。细节理解题。根据第一段内容可知, 香蕉易受病害威胁是因为其遗传上的抗病弱点。后文也有叙述。
小题3:选C。细节理解题。根据第二段前两句可知A项错误; 根据第二段第二句可知这种疾病威胁香蕉作物的根部, B项错误; 根据第二段后三句可知, 这种香蕉疾病已影响到东南亚、澳大利亚和南非, 有可能传播到美洲, D项错误。由文章前两段分别对两种真菌病的描述可知, C项正确。
小题4:选B。推理判断题。根据第三段中“The group has headquarters in France”可知其中心位于法国, A项错误; 根据第三段第三句可知, 应对这种疾病的办法是培育改良品种, 而不是研究所有的品种, C项错误; 根据第三段第四句可知D项错误。由第三段最后一句可判断B项正确。
举一反三
  Ten years ago, with only about 1, 000 pandas left in the world, China was desperately trying to clone(克隆)the animal and save the endangered species(物种). That was a move similar to what Texas A & M University researchers had been undertaking for the past five years in a project called “Noah’s Ark”(诺亚方舟).
Noah’s Ark was aimed at collecting eggs, embryos(胚胎), semen and DNA of endangered animals and storing them in liquid nitrogen. If certain species should become extinct, Dr. Duane Kraemer, a professor in Texas A & M’s College of Veterinary Medicine, said there would be enough of the basic building blocks to reintroduce the species in the future.

It was estimated that as many as 2, 000 species of mammals, birds reptiles would become extinct in over 100 years. The panda, native only to China, was in danger of becoming extinct in the next 25 years.
This week, Chinese scientists said they grew an embryo by introducing cells from a dead female panda into the egg cells of a Japanese white rabbit. They were then trying to implant the embryo into a host animal.
The entire procedure could take from three to five years to complete.
“The nucleus transfer(核子移植)of one species to another is not easy, and the lack of available(capable of being used)panda eggs could be a major problem,”Kraemer believed. “They will probably have to do several hundred transfers to result in one pregnancy(having a baby). It takes a long time and it’s difficult, but this could be groundbreaking science if it works. They are certainly not putting any live pandas at risk, so it is worth the effort, ”added Kraemer, who was one of the leaders of the project at Texas A& M, the first-ever attempt at cloning a dog.
“They are trying to do something that’s never been done, and this is very similar to our work in Noah’s Ark. We’re both trying to save animals that face extinction. I certainly appreciate their effort and there’s a lot we can learn from what they are attempting to do. It’s a research that is very much needed. ”
At present, the project has worked. The number of the pandas has increased to more than 1, 500.
小题1:The aim of “Noah’s Ark” project was to    .
A.make efforts to clone the endangered pandas
B.save endangered animals from dying out
C.collect DNA of endangered animals to study
D.transfer the nucleus of one animal to another
小题2: According to Professor Kraemer, the major problem in cloning pandas would be the lack of    .
A.available panda eggs   B.host animals
C.qualified researchersD.enough money
小题3: The best title for the passage may be    .
A.China’s Success in Pandas Cloning
B.The First Cloned Panda in the World
C.Exploring the Possibility to Clone Pandas
D.China—the Native Place of Pandas Forever
小题4:From the passage we know that    .
A.Kraemer and his team had succeeded in cloning a dog
B.scientists tried to implant a panda’s egg into a rabbit
C.Kraemer would work with Chinese scientists in clone researches
D.about two thousand species would probably die out in a century

题型:不详难度:| 查看答案
  It was July 1976. An unmanned spaceship, Viking One, had arrived at Mars. On July 20th, the spaceship  . Part of it continued toward a landing on the planet. It fell  through the late afternoon Mars’ sky.
Forty kilometers above the planet, the thin  began to slow its fall. Six kilometers above the planet a big parachute(降落伞)opened. The landing craft fell more slowly. Then, three rocket engines  . And the landing craft set down  on the surface.   in the Viking One Lander immediately sent a message to the earth. It said, “I am here. I am down safely. I am beginning my work. ”
The message  at the speed of light. It took twenty minutes to reach the earth, more than three hundred and twenty million kilometers  . Scientists and engineers at the control center  .
Moments later, television receiver in the control center began to  the first picture from Viking One. People at the center could see the feet of the landing craft sitting firmly on the 11 soil of Mars. Those pictures were our first  look at the planet. They showed a red surface, full of rocks, with no sign of  . It was our first look at a planet that is full of surprises, mysteries and promise. Viking One was launched toward Mars in August, 1975. The spaceship had two  : an orbiter(轨道飞行器)and a lander(着陆器). The orbiter would circle  Mars. It would take pictures of Mars’ surface. It would  the atmosphere.
The  would go down to the surface. It would carry  to dig up and study soil and  .
It also would report about any evidence of life on the planet. The lander would send this  to the orbiter and then back to the earth.
小题1:
A.separated      B.appeared
C.workedD.started
小题2:
A.correctlyB.slowlyC.quickly  D.directly
小题3:
A.airB.universe
C.spaceD.atmosphere
小题4:
A.firedB.fell C.openedD.floated
小题5:
A.heavilyB.softly
C.suddenly D.immediately
小题6:
A.A computer B.A rocket
C.A pilotD.An astronaut
小题7:
A.spreadB.traveled C.shot D.moved
小题8:
A.farB.long C.distantD.away
小题9:
A.shouted B.watched
C.cheeredD.welcomed
小题10:
A.makeB.take C.show D.search
小题11:
A.redB.brownC.gray D.black
小题12:
A.carefulB.closeC.real D.clear
小题13:
A.menB.life C.treesD.air
小题14:
A.partsB.rocketsC.enginesD.centers
小题15:
A.throughB.towardsC.over D.around
小题16:
A.enter B.examine
C.collectD.discover
小题17:
A.orbiterB.lander
C.spaceshipD.rocket
小题18:
A.engineers B.astronauts
C.parachutesD.instruments
小题19:
A.surfaceB.treesC.rocksD.pictures
小题20:
A.spaceshipB.rocket
C.landerD.information

题型:不详难度:| 查看答案
One night in March 1999, a man was driving from California to Oregon, US, to visit some friends. He had stopped his car to have some food when he started to hear strange noises. Turning on the headlights, he saw an 8-foot-tall creature covered in thick, dark hair. The creature stared at him for a minute, turned in the road and walked off slowly into the woods.

In the past 50 years alone, there have been thousands of reported sightings of similar creatures in the US, Canada, the Himalayas(喜马拉雅山地区)and even Hubei Province in China. The creature is known as bigfoot.
Bigfoot is said to be a very tall(between 2 and 4. 5 metres), ape-like(类人猿似的)creature that is covered in hair and walks upright on two legs. It is very wary(警惕的)of human beings.
Believers think bigfoot is a direct descendent(后代)of ancient gigantopithecus(巨猿). But it remains one of the planet’s undiscovered secrets. There is a little evidence(证据)to support the believers’ theory: traces of hair, footprints and body prints as well as the reported sightings. Some people have even showed what they say with photos or films of bigfoot.
But so far, no one has found bones or any other definite proof that the giant creature exists.
As a result many people believe the evidence is just part of a big trick.
The footprints are easy to make and they say: all you need to do is to make two large feet out of plaster(石膏), attach them to the bottom of your shoes and walk with big steps. As for the photos and films, they are just people dressed in ape suits.
They also say the sightings are not real, just people making mistakes. For example, bigfoot could be a bear living in the wild that sometimes stands up on its back legs.
小题1: So far what we can be sure about is that    .
A.there exist savages(野人)in several places in the world
B.there are some traces of hair, footprints and body prints of the “bigfoot”
C.bigfoot is a direct descendent of ancient gigantopithecus
D.all the big foot discovered have the same look
小题2:It was in   that man first found the ape-like creature.
A.1999 B.the 1960’s
C.the 1950’sD.the 1940’s
小题3: The article infers but doesn’t say so that some people    bigfoot’s existence.
A.may fool the world into believing
B.have definite evidences to prove
C.refuse to believe
D.will soon offer proofs of
小题4:If bigfoot is just a misunderstanding, what they saw might NOT be    .
A.apes
B.bears
C.gigantopithecus
D.people dressed in animal skins

题型:不详难度:| 查看答案
You may be fascinated with pictures of animals in the wild. You might have imagined yourself taking pictures of animals that are rarely seen in the city. If you do get that chance, you may want to consider the following tips or rules.

First of all, a lot of professional photographers give respect to these animals and the environment they are in. Just remember that you should respect the animals and the environment in case these animals bite or hurt you.
Keep in mind that you are taking pictures of real, live, wild animals. A wild animal may bite to protect itself. You must be sensitive while taking their pictures and be gentle in all your movements. Do not feed the animals, or interact with animals that are sleeping or caring for their young.
If you are going to a place where it is privately(私人)owned, you’d better get the owner’s permission first before you start taking pictures.
Change the flash of your camera to natural light, so the animals will not be frightened or surprised when you start shooting. Animals do not react well when they are surprised.
Be very patient. Make sure you are aware of the changes in behavior of the animal and its moods. Be familiar with the animals’ natural habitat.
Now if those rules are clear, it is time for planning. Consider the weather; some animals do not go out when it is raining while some animals love the rain. Therefore, a little research on the weather will not hurt. You should consider taking pictures after sunrise and before sunset. Now if the animal is nocturnal(夜间活动的), then you should prepare to battle not only the wild but also the darkness.
An adventure in the wild will make you very excited. However, you should be well equipped, have experts to back you up, and also a permit for doing the photo shoot. If you do not have any of these, then maybe you should consider visiting the zoo instead.
小题1:The main purpose of the author in writing this passage is   .
A.to call for us to protect animals
B.to show where to buy pictures of animals
C.to explain how to get along with wild animals
D.to give us tips on taking pictures of animals in the wild
小题2:Which of the following aspects is NOT mentioned in the passage?
A.Respecting the animals.
B.Making gentle movements.
C.Making the animals happy.
D.Changing the flash of your camera to natural light.
小题3: If the animals are on a farm owned by a person, we should   .
A.ask the owner to take pictures for us
B.ask for the owner’s permission first
C.make sure the owner is present when we take pictures
D.take pictures when the owner is feeding animals
小题4: We can infer from the passage that   .
A.most animals love being taken pictures of
B.we have to finish the pictures before sunset
C.we’d better take pictures when the animals are sleeping
D.we should pay attention to the animals’ moods when taking pictures
小题5:What preparation should you do before going to take pictures of wild animals?
①Preparing some food to feed the animals.
②Asking experts for advice.
③Knowing the weather in the animals’ habitat.
④Getting a permission for taking pictures of wild animals.
A.①②④B.②③④C.①②③D.①③④

题型:不详难度:| 查看答案
Have you seen a yellow-and-black salamander (火蜥蜴)? How about a scarlet frog? Scientists haven’t spotted either species in more than 20 years. What happened to them? Are the creatures still out there, or are they extinct?
Those are questions that scientists hope to answer. They recently set out around the world in search of those and other long-missing amphibians. An amphibian is an animal that spends part of its life in water and part on land. Frog, toads(蟾蜍), and salamanders are amphibians.
The experts are looking for about 100 species. They are searching at least 14 countries on five continents. They will look for the salamander in North America. They hope to find the scarlet frog in South America. They’re also looking for species in Africa, Asia and Australia.
Scientists are hopeful that they’ll find the amphibians—and soon! If the creatures are out there, they may need help. Many amphibians are endangered. The animals face many dangers including pollution and diseases. People cut down the forests where they live.
“If researchers can find the missing creatures, they might be able to figure out how to save them,” explains expert Robin Moore. He began searching for the amphibians earlier this month.
“This search will tell us a lot about how amphibians are doing,” Moore told WR News. “I don’t know what we will find, but that makes the search even more exciting.”
Lost in the Wild
Scientists’ hunt for missing amphibians is under way. Read about some of the species they hope to find.
Turkestanian salamander
This salamander is a mystery to scientists. Experts found a few of them more than 100 years ago, but none have been seen ever since.
Gastric brooding frog
Experts first discovered this frog in 1914 in eastern Australia. It may be extinct because of disease and habitat loss.
Rio Pescado stubfoot toad
Last sighting: 1995, in South America
Scientists hope to find this spotted toad in rivers and rainforests in Ecuador. The animal faces threats including pollution and disease.
小题1: Which of the following animals hasn’t been seen for over a century?
A.Rio Pescado stubfoot toad.
B.Gastric brooding frog.
C.Turkestanian salamander.
D.Scarlet frog.
小题2:It can be learned from the passage that _____.
A.the scarlet frog used to live in Africa
B.researchers have no way to save amphibians
C.the scientists will search 14 countries at most
D.Robin Moore has begun his search for amphibians
小题3: Why do the scientists want to find the missing amphibians?
A.Because they want to rescue the missing amphibians.
B.Because they want to set up a scientific program.
C.Because they want to do a scientific research on the missing amphibians.
D.Because they want to publish a report about the missing amphibians on WR News.
小题4: What does Moore think of the search for endangered amphibians?
A.It’s hopeful.B.It’s interesting.
C.It’s tiring.D.It’s dangerous.

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