A、Comfort. B、Safety C、Speed. D、Size. A细节题。对话结尾处女士提到，像男士这样买自行车是为了上下班和锻炼，最重要的一点就是要舒服(comfort)，故答案为A)。

W: Hi, John.
M: Oh, hi, Laura. What are you doing here?
W:[12]Er, I’m usually here on weekends. It’s my dad’s shop. So you’re looking for a bike...
M: Yeah. Now the weather is warming. I thought I’d get some exercise instead of taking the bus all the time.
W: Well, you came to the right place. Do you know what you’d like?
M: Well, I don’t want a racer or a touring bike or anything. Mostly, I’ll just be using it to get me back and forth from work.
W: How far is that?
M: About four miles.
W: Are there a lot of hills on the way?
M: Some I guess. But, maybe I should just tell you frankly that I’ve only got 150 dollars. Can I get anything decent for that?
W: Well, you’re not going to get anything top of the line,[14]but we do have a few trade-ins in the back that are in good condition.
M: That sounds good.
W:[15]For the kind of riding you’re going to be doing, the most important thing is comfort. You have to make sure it’s the right height for you. Follow me and I’ll show you what we’ve got!
12. Why is the woman at the bicycle shop?
13. Why does the man want to buy a bicycle?
14. What does the woman suggest the man do?
15. What does the woman think is the most important thing for the man when choosing a bike?