单项选择题
M: I’m afraid I must be going now.
W: Must you It’s still early.
M: I’m afraid I really must. I have to meet a midnight plane.
W: In that case, we can’t keep you.
M: Well, thank you very much for a pleasant evening.
W: Thank you for coming. You must come again.
M: Thank you. I will. Goodbye.
W: Goodbye. I wish you a very good journey home.
A．Because he is too tired.
B．Because he is catching a flight.
C．Because he does not like to stay.