founded in 1636,harvard is one of the most famous universities in the united states 为什么用founded,动词放句不是只有to do 和doing两种形式

问题描述:

founded in 1636,harvard is one of the most famous universities in the united states 为什么用founded,动词放句不是只有to do 和doing两种形式吗?

这实际上是被动语态,省略了be动词动词放在句首还可以有原形形式。