英语翻译It is only when he looks back on how he has grown up ____34____ he begins to understand his father’s unselfish love.答案that

英语翻译It is only when he looks back on how he has grown up ____34____ he begins to understand his father’s unselfish love.答案that
英语翻译
It is only when he looks back on how he has grown up ____34____ he begins to understand his father’s unselfish love.
答案that

英语翻译It is only when he looks back on how he has grown up ____34____ he begins to understand his father’s unselfish love.答案that
只有当他长大后回首往事时,他才开始理解他父亲无私的爱.
语法的话,that是通用类
如果先行词被the only,the very,the same,the last,the best等词修饰,关系代词常用that(指人时,可以用who),例如：
This is the very book that I want to find.
That is the best film that we have seen.
I was the only person in my office that/who was invited.

只有当他回顾他的成长历程时他才开始理解他父亲无私的爱
此处that 做表语的引导词 it is 状语+that

只有回首往事才懂得父爱的无私。
楼上的语法说的对。

强调句结构，it is + 强调部分+that , 这里是强调时间