Passage

Before buying a used bicycle, inspect the brakes, chain, tires, and frame. A brief test ride can reveal problems that are not obvious at first glance.

Question

What is the author's primary purpose?

Answer

To advise readers how to assess a used bicycle before purchase.

Solution

1. The passage gives practical steps and a reason for taking them.
2. It is not narrating an event or debating a policy.
3. Its purpose is to provide buying advice.