—  What were you doing when Tony phoned you?

—  Oh,I________for my father from Beijing at the station.[ ]

A. was waiting  

B. had waited

C. am waiting  

D. have waited

阅读材料，回答下列问题。

材料一2

材料二

材料三

分析中国与美国加强包括金融在内的各项经贸合作的经济学依据。