This is one of the longest bridges that ______on this river.

问题描述:

This is one of the longest bridges that ______on this river.
A is ever built B have ever been built C was ever built D has ever been built
选B 为什么不选D 不是单三么?

这种情况下(one of ...s) 后面的定语从句修饰的是 后面的复数名词.