West B Test Reading: Main Idea and Details 3 — Questions and Answers
Question 1: Read the following: 'The Amazon rainforest produces 20% of Earth's oxygen. It is home to 10% of all species on the planet and contains medicinal plants used to treat cancer and malaria. Despite this, deforestation continues at an alarming rate.' What is the main idea?
- The Amazon rainforest produces enormous amounts of oxygen
- Deforestation of the Amazon is happening quickly
- The Amazon rainforest is a vital and irreplaceable resource that is under threat (Correct answer)
- Medicinal plants in the Amazon can cure serious diseases
Correct answer: The Amazon rainforest is a vital and irreplaceable resource that is under threat
The paragraph presents the Amazon's enormous value and then highlights the threat it faces — that contrast is the main idea.
Question 2: Which question is MOST helpful for identifying the main idea of a paragraph?
- What is the most surprising fact in this paragraph?
- What is the author mainly trying to say about this topic? (Correct answer)
- What is the longest sentence in this paragraph?
- What vocabulary words are unfamiliar?
Correct answer: What is the author mainly trying to say about this topic?
Asking what the author is mainly trying to say focuses the reader on the central message rather than peripheral details.
Question 3: A passage about electric vehicles includes these details: lower fuel costs, reduced emissions, government tax credits, and quieter operation. A good main idea sentence for this passage would be:
- Electric vehicles cost less to fuel than gasoline cars
- Electric vehicles offer numerous advantages for consumers and the environment (Correct answer)
- The government provides tax credits for electric vehicle purchases
- Electric vehicles operate more quietly than traditional cars
Correct answer: Electric vehicles offer numerous advantages for consumers and the environment
Only option B is broad enough to encompass all four supporting details listed in the passage.
Question 4: A topic sentence states: 'Regular physical exercise benefits both the mind and the body.' Which detail does NOT support this main idea?
- Exercise releases endorphins that improve mood
- Aerobic activity strengthens the cardiovascular system
- Many people prefer outdoor exercise to indoor gyms (Correct answer)
- Strength training increases bone density and muscle mass
Correct answer: Many people prefer outdoor exercise to indoor gyms
Preference for outdoor versus indoor exercise is about personal choice, not about exercise benefiting mind and body.
Question 5: A passage contains many specific examples but no clear topic sentence. To identify the main idea, the reader should:
- Assume the passage has no main idea
- Look for the idea that all examples have in common (Correct answer)
- Choose the first example as the main idea
- Skip to the last sentence for the conclusion
Correct answer: Look for the idea that all examples have in common
When a main idea is implied rather than stated, readers find it by identifying what all examples share.
Question 6: A teacher asks students to distinguish between a topic and a main idea. Which explanation is correct?
- The topic and main idea are two terms for the same concept
- The topic is a word or phrase; the main idea is a complete statement about the topic (Correct answer)
- The main idea is shorter than the topic
- The topic is always the first sentence; the main idea is the last
Correct answer: The topic is a word or phrase; the main idea is a complete statement about the topic
A topic names the subject (e.g., 'climate change'), while the main idea makes a specific claim about it (e.g., 'Climate change threatens coastal cities').
Question 7: A passage begins: 'Despite decades of research, scientists still disagree about the exact cause of dinosaur extinction.' The rest of the paragraph presents three competing theories. The main idea of this paragraph is:
- An asteroid impact caused the dinosaurs to go extinct
- The exact cause of dinosaur extinction remains scientifically debated (Correct answer)
- Volcanic activity may have killed the dinosaurs
- Scientists have been studying dinosaurs for many decades
Correct answer: The exact cause of dinosaur extinction remains scientifically debated
The opening sentence signals uncertainty and debate, and the rest of the paragraph supports that idea with multiple theories.
West B Test Reading: Main Idea and Details 3
Read the following: 'The Amazon rainforest produces 20% of Earth's oxygen.
It is home to 10% of all species on the planet and contains medicinal plants used to treat cancer and malaria.
Despite this, deforestation continues at an alarming rate.' What is the main idea?