分类：教育/科学-外语学习-英语考试
问题：帮忙看个选择题Charlesinsistedthathe____ 
 insisted that he____everything he could to make sure of Lucy's happiness.A. do     B. does    C. did     D.  must do答案是A，为什么？我选的是C
回答：insist后面的宾语从句用虚拟语气，谓语动词用(should)+do,