听力原文：

B: How about going home by subway, Grace?

G: I’d love to. Taking the subway is the fastest way to go home.

B: Where is the booking office?

G: Just go straight and you can find it around the corner.

B: How often does the subway train come?

G: About every five minutes.

B: Can we get in now?

G: Please wait for another five minutes. I have to go to the bathroom.

B: You drank too much.

Question: How often does the subway train run?

参考答案: 

About every five minutes.