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2019年12月21日朗阁雅思阅读考题预测

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今天,要和大家分享的是2019年12月21日的朗阁雅思阅读考题预测,希望这篇文章能够对大家的学习有所帮助!

Passage 1

The Sound of Dolphin

A

Each and every dolphin has a different sound just like you and me, a sound that other dolphins recognize as a particular individual. Even a new baby dolphin, (calf), can detect it's mother's whistle within the pod soon after birth. Utilizing their blowholes, air sacks and valves, dolphins can emit a very wide variety of sounds. In fact, the frequency levels range 10 times beyond what humans can hear.

 

B

This system is called "Echolocation", or "Sonar", just like what a submarine uses to navigate while underwater. Yet the dolphins sonar is much more advanced than human technology and can pin point exact information about if s surroundings ranging from size, distance and even the nature of the object.

 

C

Millions of years ago, toothed whales developed echolocation, a sensory faculty that enabled them to survive in often murky and dark aquatic environments. It is a process in which an organism probes its environment by emitting sounds and listening to echoes as the sounds bounce off objects in the environment. With sound traveling better in water than electromagnetic, thermal, chemical, or light signals, it was advantageous for dolphins to evolve echolocation, a capability in which acoustic energy is used, in a sense, to see underwater. Synonymous with the term "sonar" (sound navigation and ranging) and used interchangeably, dolphin echolocation is considered to be the most advanced sonar capability, unrivaled by any sonar system on Earth, man-made or natural.

 

D

Dolphins identify themselves with a signature whistles. However, scientists have found no evidence of a dolphin language. For example, a mother dolphin may whistle to her calf almost continually for several days after giving birth. This acoustic imprinting helps the calf learn to identify its mother. Besides whistles, dolphins produce clicks and sounds that resemble moans, trills, grunts and squeaks. They make these sounds at any time and at considerable depths. Sounds vary in volume, wavelength, frequency and pattern. Dolphins produce sounds ranging from 0.25 to 150kHz. The lower frequency vocalizations (0.25 to 50 kHz) are likely used in social communication. Higher frequency clicks (40 to 150 kHz) are primarily used in echolocation. Dolphins rely heavily on sound production and reception to navigate, communicate, and hunt in dark or murky waters. Under these conditions, sight is of little use. Dolphins can produce clicks and whistles at the same time.

 

E

As with all toothed whales, a dolphin's larynx does not possess vocal cords, but researchers have theorized that at least some sound production originates from the larynx. Early studies suggested that "whistles" were generated in the larynx while "clicks" were produced in the nasal sac region. Technological advances in bio-acoustic research enable scientists to better explore the nasal region. Studies suggest that a tissue complex in the nasal region is most likely the site of all sound production. Movements of air in the trachea and nasal sacs probably produce sounds.

 

F

The process of echolocation begins when dolphins emit very short sonar pulses called clicks, which are typically less than 50-70 millionth of a second long. The clicks are emitted from the melon of the dolphin in a narrow beam. A special fat in the melon called lipid helps to focus the clicks into a beam. The echoes that are reflected off the object are then received by the lower jaws. They enter through certain parts of the lower jaw and are directed to ear bones by lipid fat channels. The characteristics of the echoes are then transmitted direct to the brain.

 

G

The short echolocation clicks used by dolphins can encode a considerable amount of information on an ensonified object - much more information than is possible from signals of longer duration that are emitted by manned sonar. Underwater sounds can penetrate objects, producing echoes from the portion of the object as well as from other surfaces within the object. This provides dolphins with a way to gain more information than if only a simple reflection occurred at the front of the object.

 

H

Dolphins are extremely mobile creatures and can therefore direct their sonar signals on an object from many different orientations, with slightly different bits of information being returned at each orientation; and since the echolocation clicks are so brief and numerous, the multiple reflections from internal surfaces return to the animal as distinct entities and are used by the dolphin to distinguish between different types of objects. Since they possess extremely good auditory-spatial memory, it seems that they are able to "remember" all the important information received from the echoes taken from different positions and orientations as they navigate and scan their environment. Dolphins' extremely high mobility and good auditory spatial memory are capabilities that enhance their use of echolocation. With much of the dolphin's large brain (which is slightly larger than the human brain) devoted to acoustic signal processing, we can better understand the evolutionary importance of this extraordinary sensory faculty. Yet no one feature in the process of echolocation is more important than the other. Dolphin sonar must be considered as a complete system, well adapted to the dolphin's overall objective finding prey, avoiding predators, and avoiding dangerous environments.

 

I

This ideal evolutionary adaptation has contributed to the success of cetacean hunting and feeding and their survival as a species overall. As a result, dolphins are especially good in finding and identifying prey in shallow and noisy coastal waters containing rocks and other objects. By using their sonar ability, dolphins are able to detect and recognize prey that have burrowed up to 1 1⁄2 feet into sandy ocean or river bottoms - a talent that has stirred the imagination (and envy) of designers of manmade sonar.

J

Researchers, documenting the behavior of Atlantic dolphins foraging for buried prey along the banks of Grand Bahama Island, have found that these dolphins, while swimming close to the bottom searching for prey, typically move their heads in a scanning motion, either swinging their snout back and forth or moving their heads in a circular motion as they emit sonar sounds. They have been observed digging as deep as 18 inches into the sand to secure a prey. Such a capability is unparalleled in the annals of human sonar development.

 


Questions 1-5

Do the following statements agree with the information given in Reading Passage 1?

In boxes 1-5 on your answer sheet, write

TRUE   if the statement is true

FALSE   if the statement is false

NOT GIVEN  if the information is not given in the passage

1 Every single dolphin is labeled by a specific sound.

2 The system a dolphin uses as the detector could give a whole picture of the observed objects.

3 Echolocation is a specific system evolving only for animals living in a dim environment.

4 The sounds are made only in the area related to the nose.

5 When producing various forms of sounds, dolphins have the asynchronism as one characteristic.

 

Questions 6-8

Choose the correct letter, A, B, C or D.

Write your answers in boxes 6-8 on your answer sheet.

6 What feature do the sounds deep in the water emitted by dolphins possess?

A diverging

B tri-dimensional

C piercing

D striking

7 Which makes the difference between the dolphins and man when it comes to the treating of vocal messages?

A an acute sense of smell

B a bigger brain

C a flexible positioning system

D a unique organ

8 Which is the undefeatable characteristic the sonar system owned by dolphins compared with the one humans have?

A making more accurate analysis

B hiding the hunted animals

C having the wider range in frequencies

D comprising more components

 

 

Questions 9-13

Summary

Complete the following summary of the paragraphs of Reading Passage, using no more than three words from the Reading Passage for each answer.

Write your answers in boxes 9-13 on your answer sheet.

 

 

 

Whether 9................... exists or not has not been confirmed yet 10.................... is the bond between the baby dolphin and its mother. What's more, 11.................. which are like different sounds made by human are also used by dolphins .The sounds are made at certain level of depth within a specific scope from a higher frequency aimed at communicating to a lower one to echolocate. Sounds are vital to dolphins living in deep waters while 12................... is not that imperative. Similar to all toothed whales, vocal cords do not exist in 13.................... but it produces some sound. The tissue in the nasal area is perhaps to do with the sound production.

 


Answer Key

1 TRUE    2 TRUE    3 NOT GIVEN

4 FALSE    5 FALSE    6 C

7 B     8 B     9 a dolphin language

10 Whistle    11 clicks and sounds  12 sight

13 a dolphin's larynx


Going Bananas

 

A

The world's favourite fruit could disappear forever in 10 years' time. The banana is among the world's oldest crops. Agricultural scientists believe that the first edible banana was discovered around ten thousand years ago. It has been at an evolutionary standstill ever since it was first propagated in the jungles of South-East Asia at the end of the last ice age. Normally the wild banana, a giant jungle herb called Musa acuminata, contains a mass of hard seeds that make the fruit virtually inedible. But now and then, hunter-gatherers must have discovered rare mutant plants that produced seed-less, edible fruits. Geneticists now know that the vast majority of these soft-fruited plants resulted from genetic accidents that gave their cells three copies of each chromosome instead of the usual two. This imbalance prevents seeds and pollen from developing normally, rendering the mutant plants sterile. And that is why some scientists believe the world's most popular fruit could be doomed. It lacks the genetic diversity to fight off pests and diseases that arc invading the banana plantations of Central America and the small-holdings of Africa and Asia alike.

 

B

In some ways, the banana today resembles the potato before blight brought famine to Ireland a century and a half ago. But “it holds a lesson for other crops, too,” says Emile Frison, top banana at the International Network for the Improvement of Banana and Plantain in Montpellier, France. “The state of the banana”, Frison warns, “can teach a broader lesson: the increasing standardisation of food crops round the world is threatening their ability to adapt and survive.”

 

C

The first Stone Age plant breeders cultivated these sterile freaks by replanting cuttings from their stems. And the descendants of those original cuttings are the bananas we still eat today. Each is a virtual clone, almost devoid of genetic diversity. And that uniformity makes it ripe for disease like no other crop on Earth. Traditional varieties of sexually reproducing crops have always had a much broader genetic base, and the genes will recombine in new arrangements in each generation. This gives them much greater flexibility in evolving responses to disease — and far more genetic resources to draw on in the face of an attack. But that advantage is fading fast, as growers increasingly plant the same few, high-yielding varieties. Plant breeders work feverishly to maintain resistance in these standardised crops. Should these efforts falter, yields of even the most productive crop could swiftly crash. “When some pest or disease comes along, severe epidemics can occur,” says Geoff Hawtin, director of the Rome-based International Plant Genetic Resources Institute.

 

D

The banana is an excellent case in point. Until the 1950s, one variety, the Gros Michel, dominated the world’s commercial banana business. Found by French botanists in Asia in the 1820s, the Gros Michel was by all accounts a fine banana, richer and sweeter than today’s standard banana and without the latter’s bitter aftertaste when green. But it was vulnerable to a soil fungus that produced a wilt known as Panama disease. “Once the fungus gets into the soil it remains there for many years. There is nothing farmers can do. Even chemical spraying won’t get rid of it,” says Rodomiro Ortiz, director of the International Institute for Tropical Agriculture in Ibadan, Nigeria. So plantation owners played a running game, abandoning infested fields and moving to “clean” land — until they ran out of clean land in the 1950s and had to abandon the Gros Michel. Its successor, and still the reigning commercial king, is the Cavendish banana, a 19th-century British discovery from southern China. The Cavendish is resistant to Panama disease and, as a result, it literally saved the international banana industry. During the 1960s, it replaced the Gros Michel on supermarket shelves. If you buy a banana today, it is almost certainly a Cavendish. But even so, it is a minority in the world’s banana crop.

 

E

Half a billion people in Asia and Africa depend on bananas. Bananas provide the largest source of calories and are eaten daily. Its name is synonymous with food. But the day of reckoning may be coming for the Cavendish and its indigenous kin. Another fungal disease, black Sigatoka, has become a global epidemic since its first appearance in Fiji in 1963. Left to itself, black Sigatoka - which causes brown wounds on leaves and pre-mature fruit ripening - cuts fruit yields by 50 to 70 per cent and reduces the productive lifetime of banana plants from 30 years to as little as 2 or 3. Commercial growers keep Sigatoka at bay by a massive chemical assault. Forty sprayings of fungicide a year is typical. But despite the fungicides, diseases such asblack Sigatoka are getting more and more difficult to control. "As soon as you bring in a new fungicide, they develop resistance," says Frison. "One thing we can be sure of is that the Sigatoka won't lose in this battle." Poor fanners, who cannot afford chemicals, have it even worse. They can do little more than watch their plants die. "Most of the banana fields in Amazonia have already been destroyed by the disease," says Luadir Gasparotto, Brazil's leading banana pathologist with the government research agency EMBRAPA. Production is likely to fall by 70 percent as the disease spreads, he predicts. The only option will be to find a new variety.

 

F

But how? Almost all edible varieties are susceptible to the diseases, so growers cannot simply change to a different banana. With most crops, such a threat would unleash an army of breeders, scouring the world for resistant relatives whose traits they can breed into commercial varieties. Not so with the banana. Because all edible varieties are sterile, bringing in new genetic traits to help cope with pests and diseases is nearly impossible. Nearly, but not totally. Very rarely, a sterile banana will experience a genetic accident that allows an almost normal seed to develop, giving breeders a tiny window for improvement. Breeders at the Honduran Foundation of Agricultural Research have tried to exploit this to create disease-resistant varieties. Further backcrossing with wild bananas yielded a new seedless banana resistant to both black Sigatoka and Panama disease.

 

G

Neither Western supermarket consumers nor peasant growers like the new hybrid. Some accuse it of tasting more like an apple than a banana. Not surprisingly, the majority of plant breeders have till now turned their backs on the banana and got to work on easier plants. And commercial banana companies are now washing their hands of the whole breeding effort, preferring to fund a search for new fungicides instead. "We supported a breeding programme for 40 years, but it wasn't able to develop an alternative to Cavendish. It was very expensive and we got nothing back," says Ronald Romero, head of research at Chiquita, one of the Big Three companies that dominate the international banana trade.

 

H

Last year, a global consortium of scientists led by Frison announced plans to sequence the banana genome within five years. It would be the first edible fruit to be sequenced. Well, almost edible. The group will actually be sequencing inedible wild bananas from East Asia because many of these are resistant to black Sigatoka. If they can pinpoint the genes that help these wild varieties to resist black Sigatoka, the protective genes could be introduced into laboratory tissue cultures of cells from edible varieties. These could then be propagated into new, resistant plants and passed on to fanners.

 

I

It sounds promising, but the big banana companies have, until now, refused to get involved in GM research for fear of alienating their customers. "Biotechnology is extremely expensive and there are serious questions about consumer acceptance," says David McLaughlin, Chiquita's senior director for environmental affairs. With scant funding from the companies, the banana genome researchers are focusing on the other end of the spectrum. Even if they can identify the crucial genes, they will be a long way from developing new varieties that smallholders will find suitable and affordable. But whatever biotechnology's academic interest, it is the only hope for the banana. Without banana production worldwide will head into a tailspin. We may even see the extinction of the banana as both a lifesaver for hungry and impoverished Africans and as the most popular product on the world's supermarket shelves.


Questions 1-3

Complete the sentences below with NO MORE THAN THREE WORDS from the passage.

In boxes 1-3 on your answer sheet, write

Write your answers in boxes 1-3 on your answer sheet

1 Banana was first eaten as a fruit by humans almost ............... years ago.

2 Banana was first planted in ...............

3 Wild banana's taste is adversely affected by its ...............

 

 

Questions 4-10

Look at the following statements (Questions 4-10) and the list of people below, match each statement with the correct person, A-I.

Write the correct letter: A-I, in boxes 4-10 on your answer sheet.

NB  You may use any letter more than once.

List of People

A Rodomiro

B David Mclaughlin

C Emile Frison

D Ronald Romero

E Luadir Gasparotto

F Geoff Hawtin

4 Pest invasion may seriously damage banana industry.

5 The effect of fungal infection in soil is often long-lasting.

6 A commercial manufacturer gave up on breeding bananas for disease resistant species.

7 Banana disease may develop resistance to chemical sprays.

8 A banana disease has destroyed a large number of banana plantations.

9 Consumers would not accept genetically altered crop.

10 Lessons can be learned from bananas for other crops.

 

 

Questions 11-13

Do the following statements agree with the information given in Reading Passage 1?

In boxes 11-13 on your answer sheet, write

TRUE   if the statement is true

FALSE   if the statement is false

NOT GIVEN  if the information is not given in the passage

11 Banana is the oldest known fruit.

12 Gros Michel is still being used as a commercial product.

13 Banana is a main food in some countries.


Answer Key

1 ten thousand  2 South-East Asia  3 hard seeds /seeds

4 F    5 A     6 D    7 C

8 E    9 B     10 C

11 NOT GIVEN  12 FALSE    13 TURE


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