Question

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

A. to prepare
B. preparing
C. prepared
D. was preparing

Answer 1

答案B
现在分词作状语时，其逻辑主语必须和主句的主语保持一致，也就是说主句的主语是现在分词动作的执行者。现在分词作状语也可表示时间、原因、伴随情况、结果等。故选B。若句中逗号改为句号时，可选A作目的状语。