【题目】It was not until the end of the trip ______ I realized what a good feeling it was to have helped someone in trouble.
A. as B. that C. where D. when
在线课程【答案】B
【解析】句意：直到旅行的结束我才意识到帮助别人是多么让人开心的感觉。分析可知原句为not until的强调句，被强调部分为not until the end of the trip。强调句结构为it’s......that......，故选B。