—Hi Susan you look tired.—I for months for the coming celebration of our school’s 90th a

问题补充：

—Hi, Susan, you look tired.

—I for months for the coming celebration of our school’s 90th anniversary.

A. was preparing

B. have been preparing

C. had prepared

D. prepare

答案：

A. was preparing

(答案→)B. have been preparing

C. had prepared

D. prepare

解析：考查时态：句意：--你好，Susan，你看起来很累。--我一直为即将到来的学校的90周年庆典做准备。说明这几个月一直在准备，而且一直到现在都很累，用现在完成进行时，选B。