Dialogue:

M: Excuse me. Have you been waiting long?

W: Twenty minutes already.

M: Did you notice whether the No. 7 bus has passed by?

W: Not while I've been standing here. I'm also waiting for the No. 7 bus myself.

M: Good. Hot today, isn't it?

W: Yes, it is. I wish that it would rain and cool off.

M: Me, too. This is unusual for March. I don't remember it ever being so hot and dry in March before.

W: My mother and I have just moved here from Indiana. It is pretty cold there.

M: Yes, I've heard of that.

W: Do you think we've missed the has?

M: Take it easy. It never comes exactly on the half hour like it should.

Question: How often should the bus come to their stop? 

- Every twenty minutes.

- Every half an hour.

- Once a day.


Every half an hour.