Unit 20 Is this seat taken?這個(gè)位子有人坐嗎?

Unit 20 Is this seat taken?這個(gè)位子有人坐嗎?
    Is this seat taken?
    No, have a seat.
    This seat is not taken.
    Yes, it is, I'm sorry.
    No, you may have a seat.
    May I open the window?
    May I go?
    May I use your car?
    No, have a seat.
    Yes, it is, I'm sorry.