【题目】 Mary ______ all the housework, she dropped herself into the sofa, sighing with relief.
A. finished B. had finished
C. having finished D. finishing
在线课程【答案】C
【解析】
试题分析：分析句子可知，she dropped herself into the sofa是主句，后面是现在分词短语作状语，she前面是逗号，没有连词，故前面用独立主格结构的形式，Mary是逻辑主语。句意：玛丽完成所有的作业后，她坐在沙发上，叹了一口气。