London Zoo's new coral reef tank is both a showcase and a research base. Coral polyps live in partnership with algae, reefs shelter a quarter of marine species, and Attenborough argues they beat rainforests for wildlife. Warming, acidification, pollution and changing currents are killing them, so scientists are looking for hardy species and ways to make coral spawn more often.
The headings (14-19) use one heading per section, A to F. The damage causes (20-21) are all in D, and the research aims (22-23) in E. The sentence completions (24-26) jump back to B, then forward to D.
Matching headings (i-vii)
Questions 14-19
How to attack this block: Read each section for its main job, not a detail. A sets out two goals for the exhibit (show the beauty, show the research). B explains the coral-algae partnership. C is about whether the rainforest comparison is fair. D is a warning, E describes what scientists are doing about it, and F ends on hope. One heading is left over.
Question 14
Answer: vSection A, last three sentences
Which heading sums up Section A?
we want to show people how wonderful they are… However, we also want to highlight the research and conservation efforts
Question says → Passage says
Twowe want to… we also want to
educational goalsshow people how wonderful they are / highlight the research and conservation efforts
Why: Pearce-Kelly gives two aims for the exhibit, both about teaching visitors something: how wonderful reefs are, and what's being done to save them. Two goals, both educational: v.
The trap: iii (Working to lessen the problems) fits the conservation detail, but A only mentions that work as something to show the public. The actual research is described in E.
Question 15
Answer: iiSection B
Which heading sums up Section B?
algae that live within them, which in turn get protection, while their photosynthesising of the sun's rays provides nutrients for the polyps. This comfortable symbiotic relationship
Question says → Passage says
CooperationThis comfortable symbiotic relationship / in turn get protection… provides nutrients
beneath the wavesin the sea water
Why: B explains how polyps and algae help each other: the algae get protection and the polyps get nutrients. A 'symbiotic relationship' is cooperation between living things, and it happens underwater. ii.
The trap: The last sentence of B gives the 25% of marine species figure, which could pull you towards a heading about richness. That's the result of the cooperation, not the main idea.
Question 16
Answer: ivSection C, first sentence
Which heading sums up Section C?
coral reefs are often described as the 'rainforests of the sea', though the comparison is dismissed by some naturalists, including David Attenborough
Question says → Passage says
a certain phrasethe 'rainforests of the sea'
Disagreement about the accuracythe comparison is dismissed / But that is simply not true
Why: The whole section is about one label, 'rainforests of the sea', and Attenborough's view that it undersells reefs. Rejecting a description is a disagreement about how accurate the phrase is. iv.
The trap: It's easy to read C as just praising reef wildlife, because Attenborough says the sight is 'mind-blowing'. That praise is his argument against the phrase, not the section's purpose.
Question 17
Answer: viiSection D
Which heading sums up Section D?
these majestic sights are now under very serious threat… And that is just the start.
Question says → Passage says
A warningCoral reefs are dying and they are telling us that all is not well with our planet
further trouble aheadmore than 90% of reefs could be lost by 2050 / that is just the start
Why: D lists threat after threat and ends with a forecast: over 90% of reefs could be lost by 2050 unless urgent action is taken. 'That is just the start' signals more trouble coming. vii.
The trap: iii (Working to lessen the problems) tempts because D mentions the need for 'urgent action'. But D only says action is needed; nobody is doing anything yet. That starts in E.
Question 18
Answer: iiiSection E, first sentence
Which heading sums up Section E?
However, scientists are trying to pinpoint hardy types of coral that could survive our overheated oceans
Why: 'However' turns from the threats to the response. Scientists are looking for tough species and ways to boost breeding, which are efforts to reduce the damage. iii.
The trap: i (Tried and tested solutions) is the leftover heading for a reason: E's ideas are experiments in progress ('trying', 'if this can be extended'), not proven solutions.
Question 19
Answer: viSection F, last two sentences
Which heading sums up Section F?
can be shown to the public and encourage them to believe that we can do something to save the planet's reefs
Question says → Passage says
Promotingcan be shown to the public and encourage them
hopebelieve that we can do something to save the planet's reefs
Why: The point of displaying the young coral is to make the public believe the reefs can be saved. Encouraging that belief is promoting hope. vi.
The trap: F also describes labs around the world testing each other's studies, which can suggest i (Tried and tested solutions). That's the background; the 'crucial point' Pearce-Kelly makes is about giving people hope.
Multiple choice (choose TWO)
Questions 20-21
How to attack this block: D lists the threats. Human pollution and changes in ocean currents match two options. Storms, overfishing and disease sound like typical reef threats, but D never mentions them.
Question 20-21
Answer: C and E (in either order)Section D, fourth sentence
Which two causes of reef damage does the writer mention?
Other menaces include ocean acidification, sea level increase, pollution by humans, deoxygenation and ocean current changes
Question says → Passage says
the contamination of the sea from wastepollution by humans
alterations in the usual flow of waterocean current changes
Why: D's list of 'menaces' contains both. C: pollution by humans is contamination from waste. E: ocean current changes are alterations in the flow of the sea.
The trap: A (extreme storms) is the most tempting, because Pearce-Kelly mentions 'wave erosion' and 'harsh conditions'. Those are things reefs normally survive, not new causes of damage. Overfishing (B) and disease (D) never appear.
Multiple choice (choose TWO)
Questions 22-23
How to attack this block: E gives the two research aims: find species that cope with warm, acidic water, and raise breeding rates by getting corals to spawn more than once a year. The artificial reef in the options is the display tank, not a research method.
Question 22-23
Answer: B and D (in either order)Section E
Which two things are true of the London Zoo researchers?
One aim will be to carry out research on species to find those that can survive best in warm, acidic waters. Another will be to try to increase coral breeding rates.
Question says → Passage says
identify corals that can cope wellfind those that can survive best
the changed sea conditionswarm, acidic waters
speed up reproduction in some coralsincrease coral breeding rates / enabled some corals to spawn artificially
Why: E names two aims. B: finding species that survive best in warm, acidic water. D: increasing breeding rates, with artificial spawning already working for 'some corals'.
The trap: A tempts because E mentions extending artificial spawning 'for all species'. The aim there is spawning more often, not breeding more different kinds of coral. C mixes up the display tank, which is an artificial reef, with the research.
Sentence completion (ONE WORD ONLY)
Questions 24-26
How to attack this block: Two answers come from B's description of polyps and algae: what polyps catch food with, and what the algae get in return. The last comes from D, where bleaching strips reefs of something. UK and US spellings of colour are both accepted.
Question 24
Answer: tentaclesSection B, first sentence
What do coral polyps use to catch their food?
Corals are composed of tiny animals, known as polyps, with tentacles for capturing small marine creatures in the sea water.
Question says → Passage says
collect their foodcapturing small marine creatures
a number oftentacles
Why: 'A number of' needs a plural noun, and polyps catch prey with 'tentacles'. Spell it correctly.
The trap: 'Polyps' fits the grammar ('a number of polyps'), but polyps are the animals themselves, not what they use to collect food.
Question 25
Answer: protectionSection B, second sentence
What do the algae get from living inside the coral?
algae that live within them, which in turn get protection
Question says → Passage says
Algae gainalgae… in turn get
from being inside the coralthat live within them
Why: 'Gain' = 'get', and what the algae get is 'protection'. It's an uncountable noun, so no article is needed.
The trap: 'Nutrients' is in the same sentence, but they go the other way: the algae's photosynthesis provides nutrients for the polyps.
Question 26
Answer: colourSection D, second sentence
Also accepted: color
What can warmer sea water strip from coral?
Rising ocean temperatures are triggering bleaching events that strip reefs of their colour
Question says → Passage says
Increases in the warmth of the sea waterRising ocean temperatures
remove the… from coralstrip reefs of their
Why: 'Remove' matches 'strip… of', and what's removed is 'colour'. UK 'colour' and US 'color' are both accepted.
The trap: 'Life' is tempting because bleaching eventually kills reefs, but the passage's word for what is stripped is 'colour'. 'Algae' gives the colour (Section B), but the passage doesn't say algae are removed.
Section C is about Attenborough rejecting the 'rainforests of the sea' label, which is a disagreement over a phrase. It isn't about comparing wildlife numbers.
The algae get protection, and in return their photosynthesis gives the polyps nutrients. Don't write 'nutrients', which go the other way.
Words from this passage worth keeping
minuscule(A)
extremely small
invertebrate(A)
an animal without a backbone
symbiotic(B)
describing a relationship where two living things help each other
dismiss(C)
reject an idea as not worth considering
menace(D)
a threat or danger
pinpoint(E)
find or identify exactly
hardy(E)
strong enough to survive difficult conditions
blighted(E)
damaged or spoilt
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The full Cambridge 20 Test 3 reading paper: all three passages, 60 minutes, marked the second you finish with a review of every answer. Already done it? Take it again and see if the same traps still get you.
Cambridge IELTS 20, Test 3, Reading Passage 2. The passage and questions belong to Cambridge University Press and are not reproduced here. We quote short extracts only as evidence for our own commentary, and the answers are published for self-marking. Get the book for the full text, or sit the test on Langujet.
