The secretary worked late into the night a long speech for the president.A. to prepareB

问题补充：

The secretary worked late into the night, a long speech for the president.

A. to prepare

B. preparing

C. prepared

D. was preparing

答案：

A. to prepare

(答案→)B. preparing

C. prepared

D. was preparing

解析：考察分词做状语。本题中的主语the secretary与动词prepare之间构成主动关系，故使用现在分词在句中作状语。句意：那位秘书熬夜工作到很晚，在喂主席准备一个很长的演讲稿。故B正确。