Question

1. Only when 1        failed in the College Entrance Examination        I realize I should have followed my teacher’s advice.

Answer 1

1. did  "only+状语从句"位于句首时，其后句子采用倒装结构。

when引导的时间状语从句用的是一般过去时态，且主句的动作和从句的动作几乎同时发生，所以主句也应用一般过去时态。