Crop-growing skyscrapers: reading answers and analysis
By 2050 the world will need far more farmland than it has, and climate change is already wrecking harvests. Vertical farms, crops grown in controlled conditions inside city skyscrapers, promise year-round organic food with less transport and fuel. Their big weakness is the cost of artificial light, so experts think city rooftops are the likelier future.
The sentence completion (1-7) runs in passage order from paragraph 2 to the last paragraph. The TRUE / FALSE / NOT GIVEN block (8-13) starts again at the top and then jumps between paragraphs 1, 3 and 4.
Answer key and self-check
Type what you wrote and hit mark. Hide the key first if you haven't done the passage yet. Every question number jumps to its explanation.
Q
Your answer
Answer
Questions 1-7 · Sentence completion (NO MORE THAN TWO WORDS)
How to attack this block: Each sentence takes you one step further through the passage, so if you lose your place, the next sentence's keyword will find it again. Several answers sit right next to a tempting neighbour (energy and grid, trays and rails), so check what the gap's verb actually needs.
Question 1
Answer: tomatoesParagraph 2, first sentence
Which food plant is named as one already grown indoors?
The concept of indoor farming is not new, since hothouse production of tomatoes and other produce has been in vogue for some time.
Question says → Passage says
already grown indoorsindoor farming is not new / hothouse production
some food plants, includingtomatoes and other produce
Why: 'Not new' and 'has been in vogue for some time' tell you this is already happening. The only plant the passage names is tomatoes. The gap follows 'including', so it needs a plural noun.
The trap: 'Produce' sits right next to it, but 'other produce' is the general category, not a named example.
Question 2
Answer: urban centresParagraph 2, middle
Also accepted: urban centers
Where would vertical farms be built, so food travels less far?
Situated in the heart of urban centres, they would drastically reduce the amount of transportation required to bring food to consumers.
Question says → Passage says
would be located inSituated in the heart of
less need to take them long distancesdrastically reduce the amount of transportation
customersconsumers
Why: 'Located in' matches 'situated in', and 'customers' is 'consumers'. The two-word answer is 'urban centres'. 'The heart of urban centres' would be four words, over the limit.
The trap: 'Cities' appears elsewhere in the passage and means the same, but it isn't in this sentence. Copy the passage's words, and either British or American spelling of 'centres' is accepted.
Question 3
Answer: energyParagraph 4, second half
What could vertical farms produce from methane?
it would return energy to the grid via methane generation from composting non-edible parts of plants
Question says → Passage says
use methanevia methane generation
to producereturn energy to the grid
Why: The sentence links methane to one product: energy sent back to the grid. The gap after 'produce' needs a noun, and 'energy' is the only one that fits.
The trap: 'Grid' is next to it, but you can't produce a grid. 'Fossil fuel' comes in the next sentence and is something the farms would cut, not create.
Question 4
Answer: fossil fuelParagraph 4, last sentence
What would be used less because farms wouldn't need tractors and similar vehicles?
It would also dramatically reduce fossil fuel use, by cutting out the need for tractors, ploughs and shipping.
Question says → Passage says
consumption of ___ would be cutdramatically reduce fossil fuel use
agricultural vehicles would be unnecessarycutting out the need for tractors, ploughs
Why: 'Consumption' is 'use' and 'cut' is 'reduce'. Tractors and ploughs are the 'agricultural vehicles'. The two words before 'use' are your answer.
The trap: 'Energy' was the answer to question 3 and the farms would consume it, so people repeat it. The passage says the farms would cut fossil fuel, not energy.
Question 5
Answer: artificialParagraph 5, first sentence
What kind of light would vertical farms need, which counts against them?
A major drawback of vertical farming, however, is that the plants would require artificial light.
Question says → Passage says
a disadvantageA major drawback
would needwould require
Why: 'Disadvantage' is 'drawback' and 'need' is 'require'. The gap sits before 'light', so it needs an adjective: 'artificial'.
The trap: 'Natural' and 'overhead' also describe light in this paragraph, but natural overhead light is what the tall buildings lack, not what they need.
Question 6
Answer: stacked traysParagraph 6, first sentence
Also accepted: trays
What do plants grow in for the version of vertical farming that uses moving parts?
One variation on vertical farming that has been developed is to grow plants in stacked trays that move on rails.
Question says → Passage says
One form of vertical farmingOne variation on vertical farming
planting ingrow plants in
which are not fixedthat move on rails
Why: 'Form' is 'variation', and 'not fixed' paraphrases 'move on rails'. The answer is 'stacked trays', or just 'trays'. Keep the plural, because the sentence says 'which are'.
The trap: 'Rails' also moves, but the plants aren't planted in rails. The trays move on them.
Question 7
Answer: urban rooftopsParagraph 7, last sentence
Also accepted: rooftops
Where will food most likely be grown in towns and cities?
most experts currently believe it is far more likely that we will simply use the space available on urban rooftops
Question says → Passage says
The most probable developmentfar more likely
in towns and citiesurban
Why: 'Most probable' matches 'far more likely'. The experts' expectation is rooftops, not skyscrapers. 'Urban rooftops' fits in two words, and 'rooftops' alone is also accepted because the sentence already says 'in towns and cities'.
The trap: 'Skyscrapers' is in the same sentence, but the passage only says that is possible. The likely option is the rooftops.
TRUE / FALSE / NOT GIVEN
Questions 8-13
How to attack this block: Most of these test the supporters' list of advantages in paragraph 4, so read it slowly. Two statements are FALSE because they flatly contradict 'all year round' and 'eliminating the need for fertilisers'. The NOT GIVEN tests a detail about forecasting methods that the passage never discusses.
Question 8
Answer: NOT GIVENParagraph 1, second sentence
Has the way the world's population is forecast changed recently?
Applying the most conservative estimates to current demographic trends, the human population will increase by about three billion people by then.
Question says → Passage says
Methods for predicting the Earth's populationthe most conservative estimates… current demographic trends
Why: The passage uses a population forecast but says nothing about how forecasting methods work or whether they've changed. NOT GIVEN.
The trap: 'Current demographic trends' sounds like something new, which tempts people to write TRUE. 'Current' describes the trends, not a change in the method.
Question 9
Answer: TRUEParagraph 1, near the end
Have people caused some of the damage to land used for crops?
Historically, some 15% of that has been laid waste by poor management practices.
Question says → Passage says
destruction to food-producing landlaid waste
Human beings are responsiblepoor management practices / we despoiled most of the land we worked
Why: 'That' refers to the land suitable for crops, and 15% of it has been ruined by poor management, which is human activity. Paragraph 3 repeats the point: 'we despoiled most of the land we worked'.
The trap: 'Some' might seem too weak against 'most' in paragraph 3, but 'some' is still true. It doesn't contradict anything.
Question 10
Answer: FALSEParagraph 4, second sentence
Will what vertical farms grow depend on the time of year?
For instance, crops would be produced all year round, as they would be kept in artificially controlled, optimum growing conditions.
Question says → Passage says
depend on the seasonall year round / year-round production of all crops
Why: The passage says crops would grow all year round under controlled conditions. If seasons don't matter, the statement is the opposite of the passage, so it's FALSE.
The trap: Some people pick NOT GIVEN because no particular crop is named. You don't need one: 'all year round' directly contradicts 'depend on the season'.
Question 11
Answer: TRUEParagraph 3, last two sentences
Does climate change cause some damage to crops?
due to a rapidly changing climate, that is not what happens. Massive floods, long droughts, hurricanes and severe monsoons take their toll each year, destroying millions of tons of valuable crops.
Question says → Passage says
climate changea rapidly changing climate
damage to food cropsdestroying millions of tons of valuable crops
Why: The passage links a changing climate to floods, droughts and storms that destroy crops every year. That's damage caused by climate change.
The trap: The writer's link between climate and the weather events runs across two sentences, so some readers miss it and choose NOT GIVEN.
Question 12
Answer: FALSEParagraph 4, middle
Will vertical farms need fertilisers for some crops?
All the food could be grown organically, eliminating the need for herbicides, pesticides and fertilisers.
Question says → Passage says
Fertilisers will be neededeliminating the need for… fertilisers
certain cropsAll the food
Why: The passage says all the food could be organic, so there'd be no need for fertilisers. 'Needed for certain crops' contradicts 'all the food', so it's FALSE.
The trap: The word 'could' makes people hesitate. It's still the supporters' claim the statement is tested against, and it rules out fertilisers for every crop.
Question 13
Answer: TRUEParagraph 4, middle
Would vertical farming make crops less likely to suffer from infectious diseases?
The system would greatly reduce the incidence of many infectious diseases that are acquired at the agricultural interface.
Question says → Passage says
less likely to be affectedgreatly reduce the incidence
infectious diseasesmany infectious diseases
Why: The key accepts this as TRUE: vertical farming would greatly reduce many infectious diseases linked to agriculture. 'Reduce the incidence' is the 'less likely' in the statement.
The trap: NOT GIVEN is tempting on a strict reading: diseases 'acquired at the agricultural interface' sound like ones people catch through farming, while the statement is about plants. The published key reads the passage's general claim about fewer infectious diseases as TRUE.
Energy was the previous answer and the farms would use it, so people repeat it. The thing cut is fossil fuel, because tractors and ploughs would no longer be needed.
TRUE in the key, but read closely: the diseases 'acquired at the agricultural interface' sound like human illnesses, while the statement talks about plants.
Words from this passage worth keeping
conservative estimate(Paragraph 1)
a cautious guess that is deliberately on the low side
laid waste(Paragraph 1)
ruined or destroyed
in vogue(Paragraph 2)
popular or common at a particular time
proponents(Paragraph 2)
people who argue in favour of an idea
despoiled(Paragraph 3)
damaged or stripped of its value
take their toll(Paragraph 3)
cause damage or loss
prohibitively expensive(Paragraph 5)
so costly that it can't really be done
detrimental(Paragraph 7)
harmful
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The full Cambridge 11 Test 1 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 11, Test 1, Reading Passage 1. 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.
