问题
选择题
The secretary worked late into the night, ______ a long speech for the president.
A．to prepare
B．prepared
C．preparing
D．to be prepared
答案
C
题目分析：句意：秘书工作到很晚，为总统准备一个很长的演讲。这里需要非谓语动词做状语，因为the secretary和prepare是主动关系，用现在分词做状语，所以选C。