Reading 2026-07 Test 20 — IELTS Academic Reading Practice Test with Answers

基于考生回忆投稿及材料收集整理 — 非官方 IELTS 资料。

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.
- TRUE. TRUE
- FALSE. FALSE
- NOT GIVEN. NOT GIVEN
9
Rabbits were introduced to Australia to control weeds.
10
Walter Froggatt was criticised for his efforts to stop the introduction of the cane toad to Australia.
11
The average size of cane toads has increased since their introduction.
12
Australian animals can eat cane toads safely.
13
In many places cane toads are gaining control of the habitats of Australian fauna.

Reading Passage 2: Desertification

A The world's great deserts were formed by natural processes interacting over long intervals of time. During most of these times, deserts have grown and shrunk independent of human activities. Paleo deserts, large sand seas now inactive because they are stabilized by vegetation, extend well beyond the present margins of core deserts, such as the Sahara. In some regions, deserts are separated sharply from surrounding, less arid areas by mountains and other contrasting landforms that reflect basic structural differences in the regional geology. In other areas, desert fringes form a gradual transition from a dry to a more humid environment, making it more difficult to define the desert border.

B These transition zones have very fragile, delicately balanced ecosystems. Desert fringes often are a mosaic of microclimates. Small hollows support vegetation that picks up heat from the hot winds and protects the land from the prevailing winds. After rainfall the vegetated areas are distinctly cooler than the surroundings. In these marginal areas, human activity may stress the ecosystem beyond its tolerance limit, resulting in degradation of the land. By ponding the soil with their hooves, livestock compact the substrate, increase the proportion of fine material, and reduce the percolation rate of the soil, thus encouraging erosion by wind and water. Grazing and the collection of firewood reduces or eliminates plants that help to bind the soil.

C This degradation of formerly productive land - desertification - is a complex process. It involves multiple causes, and it proceeds at varying rates in different climates. Desertification may intensify a general climatic trend toward greater aridity, or it may initiate a change in local climate.

D Desertification does not occur in linear, easily mappable patterns. Deserts advance erratically, forming patches on their borders. Areas far from natural deserts can degrade quickly to barren soil, rock, or sand through poor land management. The presence of a nearly desert has no direct relationship to desertification. Unfortunately, an area undergoing desertification is brought to public attention only after the process is well underway. Often little or no data are available to indicate the previous state of the ecosystem or the rate of degradation. Scientists still question whether desertification, as a process of global change, is permanent or how and when it can be halted or reversed.

E Desertification became well known in the 1930's when part of the Great Plains in the United States turned into the "Dust Bowl" as a result of drought and poor practices in farming, although the term itself was not used until almost 1950. During the dust bowl period, millions of people were forced to abandon their farms and livelihoods. Greatly improves methods of agriculture and land and water management in the Great Plains have prevented that disaster from recurring, but desertification presently affects millions of people in almost every continent. Increased population and livestock pressure on marginal lands has accelerated desertification. In some areas, nomads moving to less arid areas disrupt the local ecosystem and increase the rate of erosion of the land. Nomads are trying to escape the desert, but because of their land-use practices, they are bringing the desert with them.

F It is a misconception that drought cause desertification. Droughts are common in arid and semiarid lands. Well-managed lands can recover from drought when the rains return. Continued land abuse during droughts, however, increases land degradation. By 1973, the drought that began in 1968 in the Sahel of West Africa and the land-use practices there had caused the deaths of more than 100,000 people and 12 million cattle, as well as the disruption of social organizations from villages to the national level.

G At the local level, individuals and governments can help to reclaim and protect their lands. In areas of sand dunes, covering the dunes with large boulders or petroleum will interrupt the wind regime near the face of the dunes and prevent the sand from moving. Sand fences are used throughout the Middle East and the United States, in the same way snow fences are used in the north. Placement of straw grids, each up to a square meter in area, will also decrease the surface wind velocity. Shrubs and trees planted within the grids are protected by the straw until they take root. In areas where some water is available for irrigation, shrubs planted on the lower one third of a dune's windward side will stabilize the dune. This vegetation decreases the wind velocity near the base of the dune and prevents much of the sand from moving.

H Oases and farmlands in windy regions can be protected by planting tree fences or grass belts. Sand that manages to pass through the grass belts can be caught in strips of trees planted as wind breaks 50 to 100 meters apart adjacent to the belts. Small plots of trees may also be scattered inside oases to stabilize the area. On a much larger scale, a "Green Wall" which will eventually stretch more than 5,700 kilometers in length, much longer than the famous Great Wall, is being planted in northeastern China to protect "sandy lands" - deserts believed to have been created by human activity.

I More efficient use of existing water resources and control of salinization are other effective tools for improving arid lands. New ways are being sought to use surface-water resources such as rain water harvesting or irrigating with seasonal runoff from adjacent highlands. Research on the reclamation of deserts also is focusing on discovering proper crop rotation to protect the fragile soil, on understanding how sand-fixing plants can be adapted to local environments, and on how grazing lands and water resources can be developed effectively without being overused.

14
Desertification poses a threat to people worldwide
15
It is difficult to describe the process of desertification
16
Desertification may alter local climates
17
People have misconceptions regarding desertification origins
18
It is hard to notice desertification in its early stages
19
Straw grids diminish the swiftness of the surface wind
20
All desert borders are difficult to define.
- YES. YES
- NO. NO
- NOT GIVEN. NOT GIVEN
21
Desertification is a reversible process.
22
Part of the Great Plains did not become a so-called "Dust Bowl" until almost 1950.
23
Nomads cannot get away from the desert because of their current land-use methods.
24
Tree fences or grass belts planted inside oases can catch sand in the wind and ______ these areas as well. The "Green Wall" is an example.
25
Water resource management and prevention of ______ are also effective in protecting lands.
26
Scientists are trying to find ______ to protect the vulnerable soil.

Reading Passage 3: The Exploration of Mars

In 1877, Giovanni Schiaparelli, an Italian astronomer, made drawings and maps of the Martian surface that suggested strange features. The images from telescopes at that time were not as sharp as today’s. Schiaparelli said he could see a network of lines, or canali. In 1894, an American astronomer, Percival Lowell, made a series of observations of Mars from his own observatory at Flagstaff, Arizona, U.S.A. Lowell was convinced a great network of canals had been dug to irrigate crops for the Martian race. He suggested that each canal had fertile vegetation on either side, making them noticeable from Earth. Drawings and globes he made show a network of canals and oases all over the planet.

The idea that there was intelligent life on Mars gained strength in the late 19th century. In 1898, H. G. Wells wrote the science-fiction classic The War of the Worlds about an invading force of Martians who try to conquer Earth. They use highly advanced technology (advanced for 1898) to crush human resistance. In 1917, Edgar Rice Burroughs wrote the first in a series of 11 novels about Mars. Strange beings and rampaging Martian monsters gripped the public’s imagination. A radio broadcast by Orson Welles on Halloween night in 1938 of The War of the Worlds caused widespread panic across America; people ran into the streets in their pyjamas—millions believed the dramatic reports of a Martian invasion.

Probes are very important to our understanding of other planets. Much of our recent knowledge comes from these robotic missions into space. The first images sent back from Mars came from Mariner 4 in July 1965. They showed a cratered and barren landscape, more like the surface of our Moon than Earth. In 1969, Mariners 6 and 7 were launched and took 200 photographs of Mars’s southern hemisphere and pole on fly-by missions, but these revealed little more information. In 1971, Mariner 9 became the first spacecraft to orbit the planet, circling every 12 hours. In 1975, the U.S.A. sent two Viking probes, each with an orbiter and a lander. The landers had sampler arms to scoop up Martian rocks and carried out experiments to try to find signs of life. Although no life was found, they sent back the first colour pictures of the planet’s surface and atmosphere from pivoting cameras.

A Martian meteorite found on Earth raised fresh doubts about the above analysis. Meteorite ALH 84001 was discovered in December 1984 in Antarctica by members of the ANSMET project. The sample was ejected from Mars about 17 million years ago and spent 11,000 years in, or on, Antarctic ice sheets. NASA’s compositional analysis revealed a kind of magnetite that on Earth is only found in association with certain micro-organisms. Some structures resemble the mineralised casts of terrestrial bacteria and their appendages, fibrils or by-products occurring in the rims of carbonate globules and pre-terrestrial aqueous-alteration regions. The size and shape of the objects are consistent with Earthly fossilised nanobacteria, but the very existence of nanobacteria is still controversial.

In 1965, the Mariner 4 probe discovered that Mars had no global magnetic field to protect the planet from potentially life-threatening cosmic and solar radiation; observations made in the late 1990s by Mars Global Surveyor confirmed this discovery. Scientists speculate that the lack of magnetic shielding helped the solar wind blow away much of Mars’s atmosphere over several billion years. After mapping cosmic-radiation levels at various depths on Mars, researchers concluded that any life within the first several metres of the planet’s surface would be killed by lethal doses of radiation. In 2007 it was calculated that DNA and RNA damage would limit life on Mars to depths greater than 7.5 metres below the surface. Therefore, the best places to look for life may be subsurface environments that have not yet been studied. The disappearance of the magnetic field may have played a significant role in Martian climate change. According to scientists’ evaluation, Mars’s climate gradually transitioned from warm and wet to cold and dry after the magnetic field vanished.

NASA’s recent missions have focused on another question: whether Mars had lakes or oceans of liquid water on its surface in the ancient past. Scientists have found hematite, a mineral that forms only in the presence of water. Thus, the 2004 Mars Exploration Rovers were designed not to look for present or past life, but for evidence of ancient liquid water. Because of Mars’s current low atmospheric pressure and temperature, liquid water cannot persist at the surface except, briefly, at the lowest shaded elevations. In March 2004, NASA announced that its rover Opportunity had discovered evidence that Mars was once a wet planet. This raised hopes that evidence of past life might still be found. Later the Mars Express orbiter detected huge reserves of water-ice at Mars’s south pole in January 2004.

Researchers from the Center for Astrobiology (Spain) and the Catholic University of the North in Chile have found an oasis of micro-organisms two metres below the surface of the Atacama Desert. SOLID, a life-detection instrument, could be used in environments similar to Martian sub-soil. “We have named it a microbial oasis because we found micro-organisms developing in a habitat rich in rock salt and other highly hygroscopic compounds that absorb water,” explained Víctor Parro of the Center for Astrobiology. “If similar microbes, or their remains, exist on Mars under comparable conditions, we could detect them with instruments like SOLID,” Parro added.

Even more intriguing is an alternative scenario proposed by the Spanish scientists. If samples on Mars were found to use DNA—as Earthly life does—it would be extremely unlikely that such a specialised, complex molecule could have evolved independently on two planets. This would indicate a common origin for Martian and Earth life. Life based on DNA might have appeared first on Mars and then spread to Earth, where it evolved into the myriad plants and creatures alive today. If that proved true, we would face a startling conclusion: we are all Martians. If not, we must continue the search for other signs of life.

27
Martian evidence found on Earth
28
Mars and Earth may share the same origin of life
29
Detailed depiction of large-scale agricultural constructions
30
A project that aims to detect life under conditions similar to those on Mars
31
Mars has undergone drastic climatic transformation
32
Scientific attempts to locate liquid water on Mars
33
How did Percival Lowell describe Mars in this passage?
- A. Arizona provides the perfect location for observation.
- B. The canals of Mars are wider than those on Earth.
- C. There are clear traces of water and agriculture similar to Earth’s.
- D. Active, mobile Martian creatures were seen through telescopes.
34
How did people change their view of Mars from the 19th century onwards?
- A. They experienced a real Martian attack.
- B. They absorbed new ideas through literary works.
- C. They learned new concepts by listening to a famous radio programme.
- D. They attended public lectures given by well-known writers.
35
According to the probes sent in the 1960s, which statement about Mars is correct?
- A. Its landscape is full of rocks and rivers.
- B. It appeared far less dynamic than Earth.
- C. It contained exactly the same substances as the Moon.
- D. Images differed completely from those taken by later probes.
36
What is the implication of the project using the technology called SOLID in the Atacama Desert?
- A. It could be employed to explore organisms under Martian-like conditions.
- B. This technology could not be used to identify life in environments similar to Mars.
- C. The Atacama Desert is the only place on Earth that suits such organisms.
- D. Life has not yet been found anywhere in the Atacama Desert.
37
According to The War of the Worlds, Martian technology surpassed that of humans in every field at the time.
38
The evidence supplied by the Viking probes has never been challenged.
39
Analysis of a meteorite from Mars discovered a substance associated with certain germs.
40
According to Víctor Parro, their project will be sent to Mars once DNA-based life has been identified on Earth.

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1. beetle
The answer is 'beetle' because the passage says the larvae of a type of beetle were a serious pest in sugar cane fields.
2. roots
The answer is 'roots' because it says the larvae ate the roots of the plant.
3. expensive
The answer is 'expensive' because chemical pesticides were described as poisonous, expensive, and difficult to remove from the ground.
4. gardeners
The answer is 'gardeners' because in the 19th century French gardeners used toads.
5. moth
The answer is 'moth' because a moth stopped the spread of prickly-pear cactus in Australia.
6. Hawaii
The answer is 'Hawaii' because cane toads were brought to Australia from Hawaii.
7. failure
The answer is 'failure' because cane toads proved to be a failure as pest control.
8. FALSE
The answer is FALSE because the outcome of introducing cane toads was not immediately obvious; it took time to see the effects.
9. NOT GIVEN
The answer is NOT GIVEN because there is no information about rabbits being introduced to control weeds.
10. TRUE
The answer is TRUE because Walter Froggatt was criticised for trying to stop the introduction of cane toads.
11. NOT GIVEN
The answer is NOT GIVEN because there is no information about the average size of cane toads increasing.
12. FALSE
The answer is FALSE because Australian animals cannot eat cane toads safely; the passage says they are poisonous to native animals.
13. TRUE
The answer is TRUE because in many places cane toads are taking over the habitats of Australian fauna.
14. E
The answer is E because the passage says desertification poses a threat to people worldwide.
15. D
The answer is D because it is difficult to describe the process of desertification, as explained in the passage.
16. C
The answer is C because the passage mentions that desertification may alter local climates.
17. F
The answer is F because people have misconceptions about the origins of desertification.
18. D
The answer is D because it is hard to notice desertification in its early stages.
19. G
The answer is G because straw grids are used to slow down the surface wind.
20. NO
The answer is NO because not all desert borders are difficult to define; the passage gives examples where borders are clear.
21. NOT GIVEN
The answer is NOT GIVEN because the passage does not say if desertification is reversible.
22. NO
The answer is NO because the passage says part of the Great Plains became the 'Dust Bowl' before 1950.
23. YES
The answer is YES because nomads cannot get away from the desert due to their current land-use methods.
24. stabilize
The answer is 'stabilize' because tree fences or grass belts can catch sand and stabilize these areas.
25. salinization
The answer is 'salinization' because water resource management and prevention of salinization are effective in protecting lands.
26. proper crop rotation
The answer is 'proper crop rotation' because scientists are trying to find proper crop rotation to protect the soil.
27. D
The answer is D because the passage discusses Martian evidence found on Earth.
28. H
The answer is H because it says Mars and Earth may share the same origin of life.
29. A
The answer is A because there is a detailed description of large-scale agricultural constructions.
30. G
The answer is G because a project aims to detect life under conditions similar to those on Mars.
31. E
The answer is E because Mars has undergone drastic climatic transformation.
32. F
The answer is F because there are scientific attempts to locate liquid water on Mars.
33. C
The answer is C because Percival Lowell described Mars as having clear traces of water and agriculture similar to Earth’s. Option B is tempting but the passage focuses on similarities to Earth, not canal width.
34. B
The answer is B because people changed their view of Mars by absorbing new ideas through literary works, not by radio or lectures.
35. B
The answer is B because probes in the 1960s showed Mars appeared far less dynamic than Earth. Option A is wrong because Mars was not full of rocks and rivers.
36. A
The answer is A because the SOLID technology could be used to explore organisms under Martian-like conditions.
37. NOT GIVEN
The answer is NOT GIVEN because there is no information about Martian technology surpassing humans in every field.
38. FALSE
The answer is FALSE because the evidence from the Viking probes has been challenged.
39. TRUE
The answer is TRUE because analysis of a meteorite from Mars found a substance linked to certain germs.
40. FALSE
The answer is FALSE because Víctor Parro’s project is not waiting for DNA-based life to be found on Earth before being sent to Mars.

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