单选题 13.Walter offered us a lift when he was leaving the office, but our work______, we declined the offer.

A、 was not finished
B、 has not been finished
C、 did not finish
D、 not having been finished

【正确答案】 D

【答案解析】our work not having been finished“我们的工作尚未完成”，为分词独立结构作状语，表示原因。注意：否定的分词短语中的否定词not必须放在整个分词短语的最前面而不能放在其后，如只能说not having been finished，而不能说having not been finished。