分类：教育/科学-外语学习
问题：高一英语选择题，请说明选与不选的原因，谢谢！Timepassed 
Time pass quickly and three weeks went by _________ we knew it.A.before  B.after C. when  D.till
回答：选择A
读懂句意即可选出正确答案。
在我们意识到之前...