英文语法结构

问题描述:

英文语法结构
Fido who was behind,got hurt by some rubbish which fell upon him:on which his master had him taken care of with the utmost tenderness.这句话中on which

这个地方其实就用个which ,语法上是完全没问题的.
我唯一能给出的解释,就是前面已有个which从句,再直接用上一个which显得太突兀.