有关as倒装句为什么是young man as he is而不是 a young man as he is不是名词前有修

as 引导的部分倒装,当名词置于句首时,前面不加任何冠词,这个是语法要求的.
比如：Boy as he was, he behaved like a girl. 他虽是个男孩,但举止却像个女孩.
Child as he is , he knows a lot of things. 尽管他是个孩子,但他知道很多事情.