of their bad habits, the boys switched from being dependent on their parents to for others.
A. Having rid; sacrificing
B. To rid; sacrifice
C. Rid; sacrificing
D. Having been rid; sacrifice
网友回答
A. Having rid; sacrificing
B. To rid; sacrifice
(答案→)C. Rid; sacrificing
D. Having been rid; sacrifice
解析：句意：摆脱坏习惯后，男孩们从依赖父母的人变成了可以为他人牺牲的人。第一空需要非谓语动词做状语，the boys和rid是被动关系，要用过去分词rid， switch from…to... （从……转向……）中to是介词，后跟doing。所以选C。