A、7:20. B、7:30. C、7:50. D、7:04. B细节推断题。对话中女士问男士为什么来这么晚，男士回答说：“对不起，但火车7:40才开，所以咱们还有10分钟买票。”可见，男士到达的时间为7:30。所以选B。

W：I heard your brother broke his leg．
M：Yes，but he’s doing fine．
Q：Whose leg is broken?

W：Why are you so late?
M：Sorry，the train leaves at 7:40，so we’ve still 10 minutes to buy our tickets．
Q：When does the man arrive?