I’m Hiroshi Tanaka, an IELTS Reading expert with nine years of experience explaining complex Cambridge IELTS passages. Below you’ll find the complete breakdown of Cambridge 20 Reading Test 3, including every passage, question type, answer, location, and explanation to help you build logic, timing, and accuracy for Band 7 + scores.
Passage 1 — Frozen Food
👉 Full Passage & Detailed Explanations: Cambridge 20 Reading Test 3 Passage 1 – Frozen Food Answers with Explanations
🔹 Questions 1–7 | Notes Completion
1 potatoes
- Keywords: South America, conserved, freezing & drying
- Location: Para 1 L4–8 (“…conserving potatoes for later consumption… froze them overnight, then trampled them…”)
- Explanation: Andean people froze and dried potatoes to preserve them.
2 butter
- Keywords: 1851, ice, rail cars
- Location: Para 2 L7–10 (“…to send butter from Ogdensburg to Boston.”)
- Explanation: Butter was the first product transported in ice-cooled rail cars.
3 meat
- Keywords: 1880, Australia, first frozen food shipped
- Location: Para 4 L6–8 (“…Australian beef and mutton was sent, frozen, to England.”)
- Explanation: The first exported frozen foods were meat products.
4 crystals
- Keywords: quick-freezing, damage, spoil
- Location: Para 6 L4–7 (“He developed quick-freezing techniques that reduced the damage that crystals caused…”)
- Explanation: Birdseye minimised crystal damage to food texture.
5 cellophane
- Keywords: packaging, see product
- Location: Para 6 L7–9 (“…introduced cellophane, the first transparent material for packaging…”)
- Explanation: Cellophane let customers see product quality.
6 tin
- Keywords: World War II, rationing
- Location: Para 8 L1–4 (“…canned foods were rationed to save tin…”)
- Explanation: Tin shortage boosted frozen-food sales.
7 refrigerator
- Keywords: 1950s, homes, freezer compartments
- Location: Para 8 L5–8 (“…by 1953, 33 million US families owned a refrigerator…”)
- Explanation: Household refrigerators expanded the frozen-food market.
🔹 Questions 8–13 | True / False / Not Given
8 NOT GIVEN – Wealth of Boston ship owners not mentioned (Para 2 L1–4).
9 TRUE – Slow freezing spoiled taste (Para 4 L8–12).
10 FALSE – Birdseye went to trap furs, not study freezing (Para 5 L1–5).
11 TRUE – Swanson used a huge advertising budget (Para 9 L4–7).
12 FALSE – Tray copied from airlines, not new (Para 9 L5–7).
13 NOT GIVEN – No comparison with other countries (Final para).
Key Idea: The frozen-food industry grew from ancient freezing methods to modern convenience meals, driven by innovation and consumer demand.
Passage 2 — Can the Planet’s Coral Reefs Be Saved?
👉 Full Passage & Detailed Explanations: Cambridge 20 Reading Test 3 Passage 2 – Coral Reefs Answers with Explanations
🔹 Questions 14–19 | Matching Headings
14 v 15 ii 16 iv 17 vii 18 iii 19 vi
🔹 Questions 20–21 | Multiple Choice – Causes of Damage
20 C – pollution 21 E – changes in ocean currents
- Location: Para D L5–9 (“…pollution by humans, deoxygenation and ocean current changes…”)
- Explanation: These factors directly damage coral reefs.
🔹 Questions 22–23 | Multiple Choice – London Zoo Research
22 B – finding hardy corals 23 D – boosting spawning rates
- Location: Para E L4–10 (“…find those that survive best… some corals spawn artificially…”)
- Explanation: Scientists breed resilient corals and accelerate reproduction.
🔹 Questions 24–26 | Sentence Completion
24 tentacles – Para B L2 (polyps use tentacles to catch food).
25 protection – Para B L4–5 (algae gain protection inside coral).
26 colour – Para D L3–5 (bleaching strips coral of colour).
Key Idea: Scientists are battling climate threats to coral reefs through research and public education, offering hope for ecosystem recovery.
Passage 3 — Robots and Us
👉 Full Passage & Detailed Explanations: Cambridge 20 Reading Test 3 Passage 3 – Robots and Us Answers with Explanations
🔹 Questions 27–33 | Matching Experts
27 A – Limit robots’ abilities for safety (Rees, Para 7)
28 C – Fear exaggerated (Richardson, Para 8)
29 B – Robot creativity decades away (Wolpert, Para 5)
30 A – Ethical treatment of robots (Rees, Para 4)
31 B – Better use on Earth than space (Wolpert, Para 2)
32 A – Good science fiction insightful (Rees, Para 10)
33 C – Some welcome intelligent robots (Richardson, Para 8)
🔹 Questions 34–36 | Sentence Completion
34 C – Ethics of altering planets (Rees & Richardson).
35 B – Extent of AI advances (Rees & Wolpert).
36 D – AI harm debate (Wolpert vs Richardson).
🔹 Questions 37–40 | Multiple Choice
37 B – Fear stems from anthropomorphism (Para 6).
38 C – AI developing independent thought (Para 7).
39 B – Robots central to science fiction (Para 11).
40 C – Unite reality and fantasy views (Final para).
Key Idea: Experts debate AI ethics and innovation — balancing hope and caution in our relationship with machines.
New Vocabulary
Refrigeration – keeping food cold to preserve it.
Polyps – tiny marine animals that form coral.
Bleaching – loss of colour due to heat.
Autonomous – self-governing or independent.
Terraforming – changing a planet to support life.
Algorithm – step-by-step rules for AI decisions.
More at 👉 IELTS Vocabulary in Context
Tips for Success
- Identify cause → effect chains in scientific texts.
- Underline names & dates for tracking chronology.
- Compare expert opinions carefully in Passage 3.
- Practise timed tests (≈ 20 min each passage).
- Always recheck grammar for ONE WORD ONLY tasks.
FAQ
Q1. What are the themes in Cambridge 20 Test 3?
Innovation (Frozen Food), Environment (Coral Reefs), and Technology (Robots & Us).
Q2. Which skills does this test develop?
Scanning facts, understanding relationships, and matching opinions.
Q3. Which passage is hardest?
Robots and Us — requires interpreting multiple viewpoints.
Q4. How to achieve Band 8 + in Reading?
Practise daily with Cambridge tests and analyse why answers are wrong.
External References
For official IELTS guidance and updates, visit the British Council, IDP IELTS, and IELTS.org.
Enhance your preparation through expert-led training at Course Line – IELTS Preparation Courses.
Next Reading Practice
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