1

Set 2: Text Structure (Intermediate)

Explanation

Answer: A

PASSAGE

Vaccines work by mimicking an infection, training the immune system to recognize a pathogen. Unlike an actual infection, however, the vaccine does not cause illness. This preparation allows the body to fight off the real disease effectively.

Which choice best describes the function of the second sentence?

A. It distinguishes the mechanism of a vaccine from that of a real disease.✓ Correct
B. It explains why vaccines are dangerous.
C. It describes the history of vaccination.
D. It lists the ingredients of a vaccine.

Detailed Explanation

Sentence 1 says it mimics infection. Sentence 2 ('Unlike') distinguishes it: it doesn't cause illness.

Key Evidence:

• "Unlike an actual infection"

• "does not cause illness"

Why others are wrong: B (It says it's safe (no illness).), C (No history.), D (No ingredients.).

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