题目内容
It was two months _______ the young man mastered the skill of running the machine introduced from Germany.
A. since B. when C. that D. before
解析:选D。句意:两个月后这个年轻人才掌握了操作这台从德国引进的机器的技巧。It was+时间段+before. . . 多长时间后才……。
练习册系列答案
相关题目