急!英语达人快来,请帮忙详细解释一道语法填空题,O(∩_∩)O谢谢!

题目

急!英语达人快来,请帮忙详细解释一道语法填空题,O(∩_∩)O谢谢!
如题：While in Kyoto, I tried to learn Japanese , I worked hard at it ,and got to a point　（where) could go around in taxis and do things.
该题出自一篇语法填空,括号内为所填答案,请问该题中,为什么要填where?跪求详细解释,谢谢!

答案

这里是一个定语从句point在这边意思为 程度,也就是说我努力学日语,终于达到了可以在日本打车出去和做一些事情的程度了这里的where相当于 at which 只用一个词的话,先行词有which,when,where,that等显然,at which和wh...