定语从句先行词遇到一个题I will tell you-----he told me last yearA.all B.

A
我告诉你他去年告诉我的事.
首先排除C.因为what不能引导定语从句.
在排除BC.因为如果填that或which的话,关系代词前面却没有名词做先行词,代替要告诉的事情.
选A,代入之后是：
I will tell you all (that) he told me last year.
all 代替要告诉的事情,做先行词.因为关系代词that在从句he told me中作宾语,可以被省略掉.
all that = what
所以这个空格填what也是可以的.
all that 不能等同于 which all