Meeting mu uncle after all these years was an ungorgettable moment,one I will always treasure.

问题描述:

Meeting mu uncle after all these years was an ungorgettable moment,one I will always treasure.
one为什么不能换成waht?

此处后面的一个句子,有两种用法,一种是完整句子,必须用one引导,因为what不能直接作主语;另一种可以用which引导,这样就是修饰moment的定语从句