Sobre este conjunto: recopilado y ligeramente editado a partir de pasajes reales recordados por quienes tomaron el examen. IELTS utiliza un banco global de preguntas, por lo que estos pasajes circulan en todo el mundo. Para ofrecerte una prueba completa y lista para practicar, se agrupan pasajes reportados en el mismo periodo — así que un conjunto puede combinar pasajes de varias fechas de examen, no de una sola sesión. Organizado para tu comodidad de estudio. Basado en recuerdos de personas que tomaron el examen — no es material oficial de IELTS.
Reading Passage 1: Australia’s Cane Toad Problem
In the north of Australia there are many sugar cane plantations, which early in the 20th century were being damaged by a particular pest. This was a species of beetle whose larvae, the infant form of the beetle, live underground in the soil in the sugar cane fields. The sugar cane plants were weakened or died because their roots were eaten by the larvae. This had serious economic consequences for sugar cane farmers. Modern pesticides were not developed until the 1940s, so farmers had to use what was available at the time. Chemicals like arsenic and copper were used, but these were not only expensive but also stayed in the environment and were poisonous to people, plants and animals. It was generally acknowledged by government, farmers and scientists that cheaper and safer methods of pest control had to be found.
A promising replacement for copper and arsenic was the use of biological control. Farmers already used some forms of biological pest control in the form of predatory and parasitic wasps and flies, insect-eating birds, and plants from different regions or countries to control pests. Common practice was to release these introduced agents into new environments, the expectation being that they would destroy resident pests. Some species of toad already had successful records as agents of biological control in gardens. For example, in 19th-century France toads were sold to gardeners at markets in Paris to eat insect pests in their gardens. In the early 20th century French sugar cane farmers first took giant toads from South America to control pests in their Caribbean sugar cane plantations. Although there is no evidence that these toads did help to control pests, sugar cane scientists then carried some of these toads from Jamaica and Barbados to Puerto Rico and from there to Hawaii.
The idea of biological control of pests was not new to Australia. For example, in 1926 there had been a highly successful prevention of the increase of the exotic prickly-pear cactus by the introduction of a moth from Argentina. This success added strength to the argument that biological control was the answer to the sugar cane industry's pest problems. Accordingly, in the early 1930s a decision was taken to introduce the giant South American toads, which in Australia are now commonly called cane toads, into Australian sugar cane plantations.
In 1935, an Australian entomologist brought 101 cane toads from Hawaii and released them in sugar cane plantations in the north of Australia. However, over the following years it became clear that the cane toads were a failure. There was a fatal flaw in the plan to use them as a form of biological control. This was that earthbound cane toads were expected to eat the mostly flying adult beetles in order to eliminate the soil-dwelling beetle larvae that ate the roots of the cane sugar plants. This, of course, cane toads could not do.
Prior to their introduction in Australia, there had been very few opponents and only one made his views public. He was a retired former Chief Entomologist from the state government of New South Wales named Walter Froggatt. He forecast that cane toads might become as great a pest in Australia as rabbits. However, Froggatt's peers rebuked him and eminent scientists branded his views 'decidedly pessimistic'. It is estimated that today as many as a hundred million cane toads form a toxic infestation which is slowly spreading throughout the land.
Cane toads are large, heavily built amphibians. Average-sized adults are 10-15 cm long and weigh more than a kilo. They have large swellings on each shoulder from which they squirt poison when they are threatened. This venom contains 14 different chemicals, but they do not appear to be harmful to humans as no-one has died in Australia from cane toad poison. Until recently there was no understanding of the toxicity of cane toad poison, but it is now clear that freshwater crocodiles, goannas (large lizards) and dingoes (wild dogs) have died after eating cane toads. Cane toads compete with native Australian fauna for food, and eat the eggs and young of ground-nesting birds. As their numbers increase, they are taking over more and more of the land where native Australian fauna live.
The lesson that can be learned from the introduction of cane toads is important. It is wrong to think that such an awful biological event could not be repeated. In this instance, the catalyst was the overwhelming consensus of support for introducing cane toads to Australia. The error was that there was little or no testing of these biological agents before they were introduced to see what unplanned effects they might have on the environment.
- 1
The larvae of a type of ________ were a serious pest in sugar cane fields.
- 2
Its larvae ate the ________ of the plant.
- 3
Chemical pesticides were unsatisfactory because they were: poisonous, ________, difficult to remove from the ground.
- 4
In the 19th century French ________ used toads.
- 5
In Australia a ________ stopped the spread of prickly-pear cactus.
- 6
Cane toads were brought to Australia from ________.
- 7
Cane toads proved to be a ________ as pest control.
- 8
The outcome of the introduction of cane toads was immediately obvious.
- A. TRUE
- B. FALSE
- C. NOT GIVEN
- 9
Rabbits were introduced to Australia to control weeds.
- A. TRUE
- B. FALSE
- C. NOT GIVEN
- 10
Walter Froggatt was criticised for his efforts to stop the introduction of the cane toad to Australia.
- A. TRUE
- B. FALSE
- C. NOT GIVEN
- 11
The average size of cane toads has increased since their introduction.
- A. TRUE
- B. FALSE
- C. NOT GIVEN
- 12
Australian animals can eat cane toads safely.
- A. TRUE
- B. FALSE
- C. NOT GIVEN
- 13
In many places cane toads are gaining control of the habitats of Australian fauna.
- A. TRUE
- B. FALSE
- C. NOT GIVEN
Reading Passage 2: How do plants talk to each other?
Research shows that plants communicate and interact with each other in surprisingly subtle and sophisticated ways.
A. In 1983, plant scientists Jack Schultz and Ian Baldwin reported that the leaves of young maple trees increased their defense systems when exposed to maples that had been damaged by plant-eating (herbivorous) insects. The injured trees, they suggested, were alerting neighbors to the presence of a predator by releasing chemical signals into the air. But the plant research community did not accept this. The results were difficult to replicate, critics pointed out. Many also questioned how it could be evolutionarily stable if it benefited neighboring plants but not the plant releasing the signal. By the late 1980s, most ecologists felt that Schultz and Baldwin's ideas had been discredited.
B. A decade later, however, a number of more carefully designed experiments began to yield convincing indications to the contrary. In 2000, evolutionary ecologist Richard Karban showed that wild tobacco plants became resistant to herbivores when grown in close proximity to sagebrush plants whose leaves had been damaged by cutting. This change appeared to be in response to chemicals – known as volatile organic compounds or VOCs – released by the sagebrush plants. Other researchers soon reported similar VOC-induced defense responses in several other plants, including lima bean, broad bean, barley, and corn. And in 2006, Karban showed that VOCs released by damaged sagebrush induce herbivore resistance in plants growing at distances of up to 60 cm, well within the range of sagebrush neighbors in nature.
C. But the question still remains: 'Why should a plant waste valuable resources on a function which has no obvious advantage for it?' One hypothesis is that external communication channels are merely an extension of within-plant signaling. In sagebrush, lima bean, and poplar, VOCs released from damaged parts of a plant induce resistance in intact sections of the same plant, suggesting that each individual plant uses the signals to coordinate its own physiological responses to protect itself. Karban agrees, saying: 'The interplant signaling we see may be a result of plants co-opting that process.' Alternatively, VOC-based signaling between plants may have been favored because it enhances the 'extended fitness' of the sender by aiding related plants of the same species: a strategy known as kin selection.
D. Over the past few years, a team led by Ariel Novoplansky of Ben-Gurion University of the Negev in Israel seems to have found proof that distress signals can be passed through the plants' roots. They planted garden pea plants in rows and subjected the first in each row to conditions similar to those experienced in a drought. They then evaluated the response by measuring the microscopic holes on leaves, known as pores, which react when there is a shortage of water. After fifteen minutes, the stressed plant was seen to be closing its pores, followed by all of its neighbors, one by one. Importantly, in a control setup where root contact between neighboring plants was blocked, pores stayed open. Meanwhile, David Johnson's team at the University of Aberdeen in Scotland have been studying the labyrinths of hair-like fungi that occur around the roots of most plants. These fungi are involved in an important two-way relationship: in exchange for sugars, they provide plants with much-needed phosphorus and nitrogen. Research in which broad bean plants were infested with aphids – small herbivorous insects – revealed that these networks also served as a channel for warning neighboring plants of the infestation.
E. Monica Gagliano of the University of Western Australia believes that plants may even use sounds to alert their neighbors. In one study, she demonstrated that chili plants growing next to fennel plants developed more quickly than seedlings grown with other chili plants. Gagliano and her colleagues suspect the chili plants were compensating for the presence of the fennel, which is known to release chemicals that inhibit the growth of other plants. Remarkably, however, when plant communication pathways – airborne volatiles, root contact, and common fungal networks – were blocked, the results begged for an alternative explanation. 'We think this other channel of communication might be acoustic,' says Gagliano. But behavioral ecologist Carel ten Cate of the University of Leiden in the Netherlands points out that taking advantage of such benefits would require sensory mechanisms yet to be described in plants. Despite widespread skepticism, Gagliano has received some encouragement. Richard Karban, for example, is cautiously enthusiastic. 'Whether or not the explanation she favors is the right one,' he says, 'I think that she's gotten results that, as a field, we need to come to grips with.'
F. Researchers believe that knowledge of this phenomenon could eventually be applied to agriculture, and lead to the cultivation of hardier crops. But all agree that there is still much work to be done. 'Applying our limited knowledge [of plant-communication mechanisms] to agriculture is a big jump,' says Johnson, 'but it is definitely on the horizon.' Nevertheless, one message has emerged loud and clear from those studying this new realm of botanical interaction: despite not possessing eyes, ears, or a nervous system, plants are anything but uncommunicative. 'When I started my PhD (in the late 1980s), all this stuff was considered very weird,' recalls Ariel Novoplansky. 'Today, there is no doubt. We now recognise that plants are capable of some very sophisticated exchanges of information with other plants. This idea is not strange anymore.'
- 14
14 Paragraph A
- i. Sending messages underground
- ii. Potential advantages for farmers
- iii. The widespread rejection of an idea
- iv. One species accelerating growth in another
- v. Some obstacles to plant communication
- vi. Evidence leading to renewed belief in a theory
- vii. New technologies which helped researchers
- viii. A suggested benefit to the sender of plant communication
- 15
15 Paragraph B
- i. Sending messages underground
- ii. Potential advantages for farmers
- iii. The widespread rejection of an idea
- iv. One species accelerating growth in another
- v. Some obstacles to plant communication
- vi. Evidence leading to renewed belief in a theory
- vii. New technologies which helped researchers
- viii. A suggested benefit to the sender of plant communication
- 16
16 Paragraph C
- i. Sending messages underground
- ii. Potential advantages for farmers
- iii. The widespread rejection of an idea
- iv. One species accelerating growth in another
- v. Some obstacles to plant communication
- vi. Evidence leading to renewed belief in a theory
- vii. New technologies which helped researchers
- viii. A suggested benefit to the sender of plant communication
- 17
17 Paragraph D
- i. Sending messages underground
- ii. Potential advantages for farmers
- iii. The widespread rejection of an idea
- iv. One species accelerating growth in another
- v. Some obstacles to plant communication
- vi. Evidence leading to renewed belief in a theory
- vii. New technologies which helped researchers
- viii. A suggested benefit to the sender of plant communication
- 18
18 Paragraph E
- i. Sending messages underground
- ii. Potential advantages for farmers
- iii. The widespread rejection of an idea
- iv. One species accelerating growth in another
- v. Some obstacles to plant communication
- vi. Evidence leading to renewed belief in a theory
- vii. New technologies which helped researchers
- viii. A suggested benefit to the sender of plant communication
- 19
19 Paragraph F
- i. Sending messages underground
- ii. Potential advantages for farmers
- iii. The widespread rejection of an idea
- iv. One species accelerating growth in another
- v. Some obstacles to plant communication
- vi. Evidence leading to renewed belief in a theory
- vii. New technologies which helped researchers
- viii. A suggested benefit to the sender of plant communication
- 20
20 Plants may send messages via their _______ according to Ariel Novoplansky of Ben-Gurion University in Israel.
- 21
21 In one study, Novoplansky's team planted rows of garden peas, and created conditions like a _______ around the first plant in each row.
- 22
22 Research at the University of Aberdeen in Scotland, meanwhile, has focused on the networks of _______ which connect the plants beneath the soil.
- 23
23 Experiments involving broad bean plants and plant-eating insects called _______ have also produced some interesting results.
- 24
24 It is likely that research into plant communication will one day help to improve our food supply.
- A. Richard Karban
- B. Ariel Novoplansky
- C. David Johnson
- D. Monica Gagliano
- E. Carel ten Cate
- 25
25 Plant communication could occur as a consequence of internal mechanisms intended to help a single plant.
- A. Richard Karban
- B. Ariel Novoplansky
- C. David Johnson
- D. Monica Gagliano
- E. Carel ten Cate
- 26
26 Attitudes towards plant communication have changed greatly in recent decades.
- A. Richard Karban
- B. Ariel Novoplansky
- C. David Johnson
- D. Monica Gagliano
- E. Carel ten Cate
Reading Passage 3: Save Endangered Language
A Ten years ago Michael Krauss sent a shudder through the discipline of linguistics with his prediction that half the 6,000 or so languages spoken in the world would cease to be uttered within a century. Unless scientists and community leaders directed a worldwide effort to stabilize the decline of local languages, he warned, nine tenths of the linguistic diversity of humankind would probably be doomed to extinction. Krauss’s prediction was little more than an educated guess, but other respected linguists had been clanging out similar alarms. Keneth L. Hale of the Massachusetts Institute of Technology noted in the same journal issue that eight languages on which he had done fieldwork had since passed into extinction. A 1990 survey in Australia found that 70 of the 90 surviving Aboriginal languages were no longer used regularly by all age groups. The same was true for all but 20 of the 175 Native American languages spoken or remembered in the US., Krauss told a congressional panel in 1992.
B Many experts in the field mourn the loss of rare languages, for several reasons. To start, there is scientific self-interest: some of the most basic questions in linguistics have to do with the limits of human speech, which are far from fully explored. Many researchers would like to know which structural elements of grammar and vocabulary—if any—are truly universal and probably therefore hardwired into the human brain. Other scientists try to reconstruct ancient migration patterns by comparing borrowed words that appear in otherwise unrelated languages. In each of these cases, the wider the portfolio of languages you study, the more likely you are to get the right answers.
C Despite the near constant buzz in linguistics about endangered languages over the past 10 years, the field has accomplished depressingly little. “You would think that there would be some organized response to this dire situation,” some attempt to determine which language can be saved and which should be documented before they disappear, says Sarah G. Thomason, a linguist at the University of Michigan at Ann Arbor. “But there isn’t any such effort organized in the profession. It is only recently that it has become fashionable enough to work on endangered languages.” Six years ago, recalls Douglas H. Whalen of Yale University, “when I asked linguists who was raising money to deal with these problems, I mostly got blank stares.” So Whalen and a few other linguists founded the Endangered Languages Fund. In the five years to 2001 they were able to collect only $80,000 for research grants. A similar foundation in England, directed by Nicholas Ostler, has raised just $8,000 since 1995.
D But there are encouraging signs that the field has turned a corner. The Volkswagen Foundation, a German charity, just issued its second round of grants totaling more than $2 million. It has created a multimedia archive at the Max Planck Institute for Psycholinguistics in the Netherlands that can house recordings, grammars, dictionaries and other data on endangered languages. To fill the archive, the foundation has dispatched field linguists to document Aweti (100 or so speakers in Brazil), Ega (about 300 speakers in Ivory Coast), Waima’a (a few hundred speakers in East Timor), and a dozen or so other languages unlikely to survive the century. The Ford Foundation has also edged into the arena. Its contributions helped to reinvigorate a master-apprentice program created in 1992 by Leanne Hinton of Berkeley and Native Americans worried about the imminent demise of about 50 indigenous languages in California. Fluent speakers receive $3,000 to teach a younger relative (who is also paid) their native tongue through 360 hours of shared activities, spread over six months. So far about 5 teams have completed the program, Hinton says, transmitting at least some knowledge of 25 languages. “It’s too early to call this language revitalization,” Hinton admits. “In California the death rate of elderly speakers will always be greater than the recruitment rate of young speakers. But at least we prolong the survival of the language.” That will give linguists more time to record these tongues before they vanish.
E But the master-apprentice approach hasn’t caught on outside the U.S., and Hinton’s effort is a drop in the sea. At least 440 languages have been reduced to a mere handful of elders, according to the Ethnologue, a catalogue of languages produced by the Dallas-based group SIL International that comes closest to global coverage. For the vast majority of these languages, there is little or no record of their grammar, vocabulary, pronunciation or use in daily life. Even if a language has been fully documented, all that remains once it vanishes from active use is a fossil skeleton, a scattering of features that the scientist was lucky and astute enough to capture. Linguists may be able to sketch an outline of the forgotten language and fix its place on the evolutionary tree, but little more. “How did people start conversations and talk to babies? How did husbands and wives converse?” Hinton asks. “Those are the first things you want to learn when you want to revitalize the language.”
F But there is as yet no discipline of “conservation linguistics,” as there is for biology. Almost every strategy tried so far has succeeded in some places but failed in others, and there seems to be no way to predict with certainty what will work where. Twenty years ago in New Zealand, Maori speakers set up “language nests,” in which preschoolers were immersed in the native language. Additional Maori-only classes were added as the children progressed through elementary and secondary school. A similar approach was tried in Hawaii, with some success—the number of native speakers has stabilized at 1,000 or so, reports Joseph E. Grimes of SIL International, who is working on Oahu. Students can now get instruction in Hawaiian all the way through university.
G One factor that always seems to occur in the demise of a language is that the speakers begin to have collective doubts about the usefulness of language loyalty. Once they start regarding their own language as inferior to the majority language, people stop using it for all situations. Kids pick up on the attitude and prefer the dominant language. In many cases, people don’t notice until they suddenly realize that their kids never speak the language, even at home. This is how Cornish and some dialects of Scottish Gaelic is still only rarely used for daily home life in Ireland, 80 years after the republic was founded with Irish as its first official language.
H Linguists agree that ultimately, the answer to the problem of language extinction is multilingualism. Even uneducated people can learn several languages, as long as they start as children. Indeed, most people in the world speak more than one tongue, and in places such as Cameroon (279 languages), Papua New Guinea (823) and India (387) it is common to speak three or four distinct languages and a dialect or two as well. Most Americans and Canadians, to the west of Quebec, have a gut reaction that anyone speaking another language in front of them is committing an immoral act. You get the same reaction in Australia and Russia. It is no coincidence that these are the areas where languages are disappearing the fastest. The first step in saving dying languages is to persuade the world’s majorities to allow the minorities among them to speak with their own voices.
- 27
Choose the correct heading for Paragraph A.
- i. data consistency needed for language
- ii. consensus on an initiative recommendation for saving dying out languages
- iii. positive gains for protection
- iv. minimum requirement for saving a language
- v. Potential threat to minority language
- vi. Value of minority language to linguists
- vii. native language program launched
- viii. Subjective ou s as a nega ve ac or
- ix. Practise in several developing countries
- x. Value of minority language to linguists
- xi. government participation in language field
- 28
Choose the correct heading for Paragraph B.
- i. data consistency needed for language
- ii. consensus on an initiative recommendation for saving dying out languages
- iii. positive gains for protection
- iv. minimum requirement for saving a language
- v. Potential threat to minority language
- vi. Value of minority language to linguists
- vii. native language program launched
- viii. Subjective ou s as a nega ve ac or
- ix. Practise in several developing countries
- x. Value of minority language to linguists
- xi. government participation in language field
- 29
Choose the correct heading for Paragraph D.
- i. data consistency needed for language
- ii. consensus on an initiative recommendation for saving dying out languages
- iii. positive gains for protection
- iv. minimum requirement for saving a language
- v. Potential threat to minority language
- vi. Value of minority language to linguists
- vii. native language program launched
- viii. Subjective ou s as a nega ve ac or
- ix. Practise in several developing countries
- x. Value of minority language to linguists
- xi. government participation in language field
- 30
Choose the correct heading for Paragraph E.
- i. data consistency needed for language
- ii. consensus on an initiative recommendation for saving dying out languages
- iii. positive gains for protection
- iv. minimum requirement for saving a language
- v. Potential threat to minority language
- vi. Value of minority language to linguists
- vii. native language program launched
- viii. Subjective ou s as a nega ve ac or
- ix. Practise in several developing countries
- x. Value of minority language to linguists
- xi. government participation in language field
- 31
Choose the correct heading for Paragraph F.
- i. data consistency needed for language
- ii. consensus on an initiative recommendation for saving dying out languages
- iii. positive gains for protection
- iv. minimum requirement for saving a language
- v. Potential threat to minority language
- vi. Value of minority language to linguists
- vii. native language program launched
- viii. Subjective ou s as a nega ve ac or
- ix. Practise in several developing countries
- x. Value of minority language to linguists
- xi. government participation in language field
- 32
Choose the correct heading for Paragraph G.
- i. data consistency needed for language
- ii. consensus on an initiative recommendation for saving dying out languages
- iii. positive gains for protection
- iv. minimum requirement for saving a language
- v. Potential threat to minority language
- vi. Value of minority language to linguists
- vii. native language program launched
- viii. Subjective ou s as a nega ve ac or
- ix. Practise in several developing countries
- x. Value of minority language to linguists
- xi. government participation in language field
- 33
Choose the correct heading for Paragraph H.
- i. data consistency needed for language
- ii. consensus on an initiative recommendation for saving dying out languages
- iii. positive gains for protection
- iv. minimum requirement for saving a language
- v. Potential threat to minority language
- vi. Value of minority language to linguists
- vii. native language program launched
- viii. Subjective ou s as a nega ve ac or
- ix. Practise in several developing countries
- x. Value of minority language to linguists
- xi. government participation in language field
- 34
Reported language conservation practice in Hawaii
- 35
Predicted that many languages would disappear soon
- 36
Experienced languages die out personally
- 37
Raised language fund in England
- 38
Not enough effort on saving until recent work
- 39
What is purpose of master-apprentice program sponsored by The Ford Foundation?
- A. Teach children how to speak
- B. Revive endangered language
- C. Preserve endangered language
- D. Increase communication between students
- 40
What should majority language speaker should do according to the last paragraph?
- A. They should teach their children endangered language
- B. They should learn at least four languages
- C. They should show their loyalty to a dying language
- D. They should be more tolerant to minority language speaker