I never thought of it before all that my parents had done for me for granted.A. takenB.

问题补充：

I never thought of it before, all that my parents had done for me for granted.

A. taken

B. to take

C. taking

D. Took

答案：

A. taken

B. to take

(答案→)C. taking

D. Took

解析：考查固定搭配和非谓语动词。take sth for granted想当然，认为......理所当然。句意：我以前从未意识到，我(竟然不知道感激)把父母对我的付出当作是理所当然的事情。I与take是主谓关系，排除A；took不能单独使用，排除D；现在分词表示伴随状况。故选C。