8. ______ for two days, Steve managed to finish his report on schedule.
A
To work
B
Worked
C
To be working
D
Having worked
本题需判断主句主语Steve是work的“施动者”，且有明显的完成时时间状语"for two days"，故选择完成时结构的现在分词，故选项D符合答案。
根据句意理解工作了两天，Steve 设法成功地完成了报告。
常见分词做状语的语法理解不准致错。