He sat rooted in his seat.请问这句中的rooted用过去分词是个什么用法?为什么选过去分词?

问题描述:

He sat rooted in his seat.请问这句中的rooted用过去分词是个什么用法?为什么选过去分词?
He sat rooted in his seat.
请问这句中的rooted用过去分词是个什么用法?为什么选过去分词?过去分词不是表被动和完成么?难道是系表结构?
如果是过去分词短语,它的选择也是表被动和完成吧?

1.这种用法叫做主语补足语,rooted in his seat是过去分词短语,说明主语He;类似的还有He stood there dumfounded.他站在那里,目瞪口呆.
2.也可以理解为rooted ...为过去分词短语,作状语表示伴随状况.