动名词作主语与宾语的用法 — 英语选择题
题目
完成句子最佳选项：Wherever she goes, Lily insists on ___ regular exercise, for she believes ___ every morning is the key to staying energetic. Which of the following completes the sentence correctly? A. doing; to run B. to do; running C. doing; running D. to do; to run