Reading 2026-09 Test 2 — 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: Carnivorous Plants

They attract insects and then eat their flesh. Is that any way for a plant to behave?

(A) The naturalist and author of On the Origin of Species, Charles Darwin, was fascinated by carnivorous plants. In 1860, soon after he came across his first carnivorous plant — the sundew, Drosera — he wrote, ‘I care more about Drosera than the origin of all the species in the world.’ He spent months running experiments on the plants. He dropped flies and bits of meat on their leaves and watched them slowly fold their sticky tentacles over their prey. He thought it incredible that brushing a leaf with a single strand of human hair was enough to bring about a response. Yet sundews, he observed, ignored raindrops. To react to such a false alarm, he reasoned, would obviously be a great evil to the plant. This was no accident. This was adaptation.

(B) Darwin expanded his studies from sundews to other species in his book Insectivorous Plants. He was amazed at the quickness and power of the Venus flytrap. He showed that when one of its leaves snapped shut, it formed itself into a temporary ‘stomach’, secreting enzymes that could dissolve the prey. He noted that a leaf took more than a week to reopen after closing, and reasoned that the interlocking spines along the margin of the leaf allowed tiny insects to escape, saving the plant the expense of digesting an insufficient meal.

(C) Today, biologists using 21st-century tools to study cells and DNA are beginning to understand how these plants hunt, eat, and digest — and how these strange adaptations came about in the first place. Alexander Volkov, a plant physiologist at Oakwood University in Alabama, believes he has figured out the Venus flytrap’s secret. ‘This,’ Volkov declares, ‘is an electrical plant.’ When an insect brushes against a hair on the leaf of a Venus flytrap, the movement sets off an electric charge. The charge builds up inside the tissue of the leaf but is not enough to stimulate the snap, which keeps the Venus flytrap from reacting to false alarms, such as raindrops. An insect, however, is likely to brush a second hair, adding enough electric charge for the leaf to close.

(D) Volkov’s experiments reveal that the electric charge travels down fluid-filled tunnels in a leaf, which opens up pores in cell membranes. Water rushes from the cells on the inside of the leaf to those on the outside, causing the leaf to rapidly flip in shape from convex to concave, like a soft contact lens. As the leaves flip, they snap together, trapping an insect inside.

(E) The bladderwort plant has an equally sophisticated way of setting its underwater trap. It pumps water out of tiny air sacs or bladders, lowering the pressure inside. When a water flea or some other small creature swims past, it bends hairs on the bladder, causing a flap to spring apart. The low pressure sucks water in, carrying the creature along with it. In one five-hundredth of a second, the flap swings shut again. The cells in the bladder then begin to pump water out again, creating a new vacuum. Many other species of carnivorous plants act like living flypaper, catching animals on sticky tentacles. Pitcher plants use yet another strategy, growing long tube-shaped leaves into which insects fall. Some of the largest have pitchers up to 30cm deep and can consume whole frogs unlucky enough to fall into them. Sophisticated chemistry helps make the pitcher a death trap.

(F) Nicholas Gotelli, of the University of Vermont, is trying to figure out what evolutionary forces pushed these plants towards meat. Carnivorous plants clearly benefit from eating animals; when scientists feed pitcher plants extra bugs, the plants get bigger. But the benefits of eating flesh are not the ones you might expect. Carnivorous animals, like ourselves, use the carbon in protein and the fat in meat to build muscles and store energy. Carnivorous plants, however, take nitrogen and phosphorus from the flesh in order to build light-harvesting enzymes. Eating animals, in other words, lets carnivorous plants do what all plants do: grow by taking energy directly from the sun. Unfortunately, they do a really bad job of it. That’s because they have to use a lot of energy to make the equipment they need to catch animals — the enzymes, the pumps, the sticky tentacles, and so on. A pitcher or a flytrap is not very good at photosynthesis because, unlike plants with ordinary leaves, it does not have flat solar panels that can absorb lots of sunlight. Gotelli suspects that only under special conditions are the benefits of being carnivorous greater than the costs. The poor soil of bogs and swamps, where many carnivorous plants grow, offers little nitrogen and phosphorus, so carnivorous plants enjoy an advantage there over ‘conventional’ plants. Also, bogs are often flooded with sunshine, so even an inefficient carnivorous plant can carry out enough photosynthesis to survive. ‘They’re stuck, and they’re making the best of it,’ says Aaron Ellison of Harvard University.

(G) Unfortunately, the adaptations that enable carnivorous plants to survive in harsh habitats also make them extremely sensitive to environmental changes. Chemical fertilizers used in agriculture and pollution from power plants are adding extra nitrogen to many bogs in North America. Carnivorous plants are so finely adapted to low levels of nitrogen that this extra fertilizer is overloading their systems. Humans also threaten carnivorous plants in other ways. The black market trade in exotic carnivorous plants is strong, but even if this can be prevented, carnivorous plants will continue to suffer from other dangers. Their habitat is disappearing, to be replaced by shopping centers and houses. The suppression of wildfires by government agencies allows other plants to grow quickly and outcompete the Venus flytraps. Good news, perhaps, for flies. But a loss for all who delight in the inventiveness of evolution.

1
He understood why the plant did not respond to ____.
2
He demonstrated how leaves close and then, for a short period, act like a ____.
3
The charge enters fluid-filled tunnels, causing ____ in cell membranes to open.
4
When water is pumped out of bladder cells, a ____ builds up inside.
5
Some plants are big enough to capture and eat ____.
6
Pitcher plants increase in size after they have digested a lot of insects.
- A. TRUE
- B. FALSE
- C. NOT GIVEN
7
Carnivorous plants produce light-harvesting enzymes with the nutrients they extract from animals.
8
Pitcher plants and Venus flytraps are more efficient at photosynthesis than plants with ordinary leaves.
9
Venus flytraps are better adapted to the soil of swamps and bogs than other carnivorous plants.
10
Carnivorous plants frequently find it difficult to photosynthesise in bogs due to a lack of sunlight.
11
Scientists have campaigned to reduce the amount of nitrogen that is released into the soil by agricultural practices.
12
A lot of exotic carnivorous plants are sold illegally.
13
Preventing wildfires is beneficial to the Venus flytrap.

Reading Passage 2: Australia's Camouflaged Creatures

Many species of animal in Australia protect themselves by using camouflage — a way of 'hiding' by blending into the surroundings.

Most species use camouflage to some extent. If they are convincing, they survive to pass their genes on to future generations. After generations of natural selection, animals can develop astonishingly complex camouflage techniques, manipulating shape, colour and movement. 'The principle of camouflage is to make it economically unviable for a predator to pursue a particular species of prey,' explains Professor Mark Elgar of the University of Melbourne. 'Camouflage increases the search time and, as a consequence, the predator will simply target another species, either because it doesn't see the camouflaged individual or it just finds something more obvious to do.'

The easiest way for an animal to disguise itself is to be invisible in its surroundings. To that end, stick and leaf insects have evolved complex camouflage to hide themselves from predators. Many have the texture of sticks or dry leaves, while others imitate living foliage, even the veins in a leaf. Some insects develop blemishes to match the spots caused by disease. A convincing appearance only works if its owner also acts the part, so during the day the creature using this type of camouflage keeps motionless, or sways like a dead leaf in the breeze. If disturbed, it falls to the ground and stays still. Entomologist Paul Zborowski, who has spent decades photographing inconspicuous creatures, rates the desert insects of Central Australia as the most convincingly disguised creatures he's seen. 'It's an incredibly old habitat, so the creatures have had a long time to adapt,' Zborowski explains. Most of them behave like stones and don't move all day, feeding only at night.

A tawny frogmouth sitting motionless on a stump also illustrates the importance of pairing a persuasive costume with behaviour. Professor Gisela Kaplan of the University of New England in Australia says the frogmouth's skill at camouflaging is learned behaviour. While adopting a pose may be a reflex of the bird, and can be observed in a hatchling's first week, the ability to choose a backdrop which matches its colouration does not develop for 4–6 months. When the chicks land, they are usually highly conspicuous, and their parents try to signal to them to move to a safe location.

Fixed camouflage is only good against a relatively unchanging environment, so some animals, such as the cuttlefish, have evolved an adaptable disguise. The cuttlefish can almost instantly change its colour, pattern and texture to match its surroundings, using specialised cells and muscles. On Queensland's reefs, scientists have been studying another ocean dweller that uses colour change, although not to blend into the surroundings. Dr Karen Cheney, from the University of Queensland, says the bluestriped fangblenny alters its colouration to mimic other species of fish, allowing it to travel with them and benefit from safety in numbers. Its most impressive impersonation is of the black-with-neon-blue-striped cleaner wrasse, which eats the parasites on larger fish. Not only does the fangblenny benefit from the reduced predation that comes with the wrasse's beneficial relationships with other fish, but the disguise also lets it get closer to prey. It darts out from the safety of the wrasse's cleaning station to nip at unsuspecting fish passing by, but it doesn't attack those coming to be cleaned.

The most famous form of mimicry, however, is for defence, not attack. Batesian mimicry refers to animals that gain protection from predators by imitating a dangerous organism, often using conspicuous colours. The nineteenth-century naturalist Henry Bates first suggested this camouflage technique after noticing that several Amazonian butterfly species looked the same. The technique was later called after him. In Australian waters, the harmless harlequin snake eel sports the same black and white bandings as the highly toxic yellow-lipped sea krait, ensuring no predator will attack. However, the success of Batesian mimicry depends on the ratio of mimics to originals. If a predator encounters too many that are edible, it will just assume none of the animals with those markings are dangerous, explains Martyn Robinson, an educational naturalist with the Australian Museum.

An imitation of a more dangerous creature needn't be exact, just enough to make potential predators hesitate. The hawk moth caterpillar has markings resembling a snake's eyes on its abdomen. When confronted, the caterpillar pulls its head in and the 'eyes' flash open. Whether the potential predator thinks it has seen a snake, or is simply startled, is unclear, but the outcome is that the caterpillar lives to see another day.

In Queensland's tablelands, the chameleon gecko has another way of making predators hesitate. Its body is brown, but its tail is banded in black and white. Robinson explains that if attacked, the chameleon gecko will drop off its tail, which will wriggle around on the ground. Many lizards do this, but in the case of the chameleon gecko the tail bones actually rub against one another, so it squeaks. 'The predator is, of course, thoroughly absorbed by this black-and-white-striped, wriggling, squeaking thing on the ground, and the gecko can sneak away,' Robinson says. It's a one-time-only trick: the regrown tail is brown, the same as the gecko's body. Such precise disguise and elaborate trickery illustrate the limitless possibilities of nature. But, as Robinson points out, only the most successful illusionists are here to tell the tale.

14
a species that indicates to its young to move to a place where they are less visible
15
an instance where sound is used to help an animal escape
16
a creature that can use camouflage to match a range of different backgrounds
17
a claim that the majority of animals disguise themselves in some way
18
examples of animals that use camouflage to look like plants
19
one species has a camouflage tactic that is not present from birth.
- A. Professor Mark Elgar
- B. Paul Zborowski
- C. Professor Gisela Kaplan
- D. Dr Karen Cheney
- E. Henry Bates
- F. Martyn Robinson
20
species that live in an ancient environment have become very effective at camouflaging themselves.
21
part of an animal is left behind to distract predators.
22
if it takes too long to find one kind of prey, animals will look for an alternative source of food.
23
camouflage can involve copying a threatening type of animal.
24
Dr Karen Cheney studies the bluestriped fangblenny on ______ off Queensland's coast. She found that the fangblenny was able to make itself resemble other fish by adjusting its colouration. The fangblenny impersonates the striped cleaner wrasse, a fish that is welcomed by other species as it gets rid of their ______. The fangblenny can approach its ______ without drawing the attention of predators or disturbing the work of the striped cleaner wrasse. (Q24–26, fill in the blanks)

Reading Passage 3: Insect-inspired robots

A recent conference reports on developments in biorobotics

A tiny insect navigates its way across featureless salt-pans. A cockroach successfully works out how to scramble over an obstacle. The mantis shrimp scans its aquatic world through hyperspectral eyes. Using the most basic of equipment and brains tinier than a pin-head, insects constantly solve complex problems of movement, vision and navigation – processing data that would challenge a super-computer. How they do it is driving one of the most exciting new fields of technology – biomimetics and biorobotics, the imitation of insect systems to control man-made machines. Delegates at a recent conference presented some outcomes of their work in this area.

Dr Alex Zelinsky suggested that the method by which wasps use landmarks to find their way back to the nest may one day be part of a system for navigating cars that know where to go. A research team led by Dr Zelinsky has shown that a robot can navigate its way among 50 different landmarks by recognising them individually using a panoramic camera. “The inspiration came from biology, where wasps use a practical method turn back and look to orient themselves as they emerge from their nest. By flying to and fro, they look at the wasp nest from different angles and perspectives so they can recognise it again,” he explained. The robot’s panoramic camera logs the surrounding area and its key landmarks, which are then stored in its computer according to how reliable they are as navigational aids. The landmarks are then scaled, from small to large, so that the robot can recognise whether it is getting closer to or further away from them. Their location is built into a map in its mind, which operates at different scales and instructs the robot whether to turn left or right at a particular mark. The technology provides a general way for a machine to navigate an unknown landscape.

For three decades, Professor Ruediger Wehner has journeyed from Switzerland to the Sahara Desert where Cataglyphis, a tiny ant with a brain weighing just 0.1 mg, performs acts of navigational genius when it leaves its nest, forages for food and returns successfully. Cataglyphis uses polarised light, caused when air molecules scatter light, to orient and steer itself. Wehner’s team found that the ant has a set of specialised photoreceptors along the upper rim of its eyes that detect polarised light, while other receptors perform different navigational tasks. As the sun moves, the ant notes its direction each time it leaves the nest and updates its internal compass. Using other eye receptors it stores a snapshot image of landmarks close to the nest entrance in its eyes and compares this with what it sees as it returns. The ant also has a way of measuring distance travelled, while a path integrator periodically informs the ant of its current position relative to its point of departure. Rather than integrate all the information it receives in its brain, the ant actually performs a number of complex calculations in different organs. Like a super-computer, the ant has many separate sub-routines going on simultaneously. Using the ant’s ability to steer by polarised light and to store and reuse landscape images, Wehner and colleagues have built “Sahabot,” a small vehicle that uses polarisers and a CCD camera to store 360° images of its surroundings. It navigates by using polarised sunlight and comparing the current images of landmarks to the ones in its memory.

Professor Robert Michelson had a different desert challenge – to design a flying robot that can not only navigate but also stay aloft and hover in the thin atmosphere of Mars. Drawing inspiration from insect flight, he has gone beyond nature to devise a completely new concept for a flying machine. The “Entomopter” is a sort of double-ended dragonfly whose wings beat reciprocally. Michelson says that the flapping-wing design gives the craft unusually high lift compared with a fixed-wing flyer, enabling it to fly slowly or hover in the thin Martian air – whereas a fixed-wing craft would have to move at more than 400 km/h and could not stop to explore.

Engineer Roger Quinn and entomologist Professor Roy Ritzmann are taking their inspiration from cockroaches. According to Quinn and Ritzmann, the ability of cockroaches to run very fast over rough terrain may one day give rise to a completely new all-terrain vehicle with six legs, or maybe even wheel-like legs called “whegs.” The key to the cockroach’s remarkable cross-country performance lies partly in the fact that its legs do a lot of the thinking without having to consult the brain. Quinn and Ritzmann are drawing on cockroach skills to create robotic walkers and control strategies that capture the remarkable capacity of these insects to traverse complex terrain and navigate safely toward goals while avoiding obstacles. The team has already designed a series of robots that run on six legs or on whegs, enabling them to handle surprisingly rugged terrain.

International experts believe there are tremendous opportunities in biorobotics. However, delegates at the conference had differing visions for the future of the science. While some were concerned that the initial applications of biorobotics may be military, others, such as Dr Barbara Webb, predicted swarms of tiny, cheap, insect-like robots as society’s cleaners and collectors. Sonja Kleinlogel hoped the study of the hyperspectral eyes of the mantis shrimp might yield remote sensors that can watch over the environmental health of our oceans. Several delegates were concerned about the ethical implications of biorobotics and urged that close attention be paid to this as the science and technologies develop.

25
positive and negative possibilities for the use of insect-inspired robots
26
how perceived size is used as an aid to navigation
27
an example of decision-making taking place in the limbs
28
a description of a potential aid in space exploration
29
the range of skills that have inspired biorobotics
30
how a variety of navigational methods operate at the same time
31
Which creature sees particularly well under water?
32
In addition to a computer, what technical equipment is fitted in Dr Zelinsky’s robot?
33
Where is the Cataglyphis ant found?
34
What atmospheric effect helps the Cataglyphis ant to know its direction?
35
Dr Alex Zelinsky
- A. a robot that makes use of light as well as stored images for navigational purposes
- B. a robot that can contribute to environmental health
- C. a robot that can move over difficult surfaces
- D. a robot that categorises information from the environment according to its usefulness
- E. a robot that can be used to clean surfaces and collect rubbish
- F. a robot that has improved on the ability of the insect on which it is based
- G. a robot that can replace soldiers in war
36
Professor Ruediger Wehner
37
Professor Robert Michelson
38
Roger Quinn and Professor Roy Ritzmann

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1. raindrops
The answer is 'raindrops' because it says he understood why the plant did not respond to raindrops, meaning the plant reacts differently to other things.
2. stomach
The answer is 'stomach' because he showed that after leaves close, they act like a stomach for a short time, digesting what is inside.
3. pores
The answer is 'pores' because the charge makes pores in cell membranes open, letting things move in or out.
4. vacuum
The answer is 'vacuum' because when water is pumped out, a vacuum builds up inside the bladder cells.
5. frogs
The answer is 'frogs' because some plants are large enough to catch and eat frogs, not just insects.
6. A
The answer is TRUE because the passage says pitcher plants get bigger after digesting many insects.
7. A
The answer is TRUE because carnivorous plants use nutrients from animals to make light-harvesting enzymes.
8. B
The answer is FALSE because the passage says pitcher plants and Venus flytraps are not more efficient at photosynthesis than ordinary plants. The tempting wrong answer is TRUE, but the passage clearly says they are not more efficient.
9. C
The answer is NOT GIVEN because there is no information about Venus flytraps being better adapted to swamp and bog soil than other carnivorous plants.
10. B
The answer is FALSE because the passage says carnivorous plants do not have trouble photosynthesising in bogs due to lack of sunlight. The tempting wrong answer is TRUE, but the passage says sunlight is not the problem.
11. C
The answer is NOT GIVEN because there is no mention of scientists campaigning to reduce nitrogen in soil from farming.
12. A
The answer is TRUE because the passage says many exotic carnivorous plants are sold illegally.
13. B
The answer is FALSE because preventing wildfires is not good for Venus flytraps; they need fires to survive.
14. C
The answer is C because this species signals its young to move to a less visible place, helping them hide.
15. G
The answer is G because there is an example where sound is used to help an animal escape from danger.
16. D
The answer is D because this creature can change its appearance to match different backgrounds, using camouflage.
17. A
The answer is A because it claims most animals use some form of disguise.
18. B
The answer is B because it gives examples of animals that look like plants to hide.
19. C
The answer is C because one species she discusses does not have its camouflage from birth, but develops it later.
20. B
The answer is B because he talks about species in ancient environments that have become very good at camouflage.
21. F
The answer is F because this person describes an animal leaving part of its body behind to distract predators.
22. A
The answer is A because he explains that if it takes too long to find one prey, animals will look for another food source.
23. E
The answer is E because he says some animals copy dangerous species as a form of camouflage.
24. reefs / parasites / prey
The answers are 'reefs', 'parasites', and 'prey' because Dr Cheney studies the fangblenny on reefs, which copies the cleaner wrasse that removes parasites, and the fangblenny can approach its prey.
25. F
The answer is F because it discusses both good and bad possibilities for using insect-inspired robots.
26. B
The answer is B because it explains how insects use perceived size to help them navigate.
27. E
The answer is E because it gives an example where the limbs make decisions, not just the brain.
28. D
The answer is D because it describes a robot that could help in space exploration.
29. A
The answer is A because it talks about the many skills from insects that inspire biorobotics.
30. C
The answer is C because it explains how insects use several navigation methods at the same time.
31. mantis shrimp
The answer is 'mantis shrimp' because it is the creature that sees especially well underwater.
32. panoramic camera
The answer is 'panoramic camera' because Dr Zelinsky’s robot uses this equipment along with a computer.
33. Sahara Desert
The answer is 'Sahara Desert' because that is where the Cataglyphis ant lives.
34. polarised light
The answer is 'polarised light' because this effect helps the ant know which direction to go.
35. D
The answer is D because Dr Zelinsky made a robot that sorts information from the environment by usefulness.
36. A
The answer is A because Professor Wehner’s robot uses both light and stored images to navigate.
37. F
The answer is F because Professor Michelson’s robot is even better than the insect it copies.
38. C
The answer is C because Quinn and Ritzmann made a robot that can move over rough ground.

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