首先，comment既是动词又是名词，commentary是名词 comment：评价。

评论 eg:Thisis the first draft of the book.Please feel perfectly free to *comment on* it.(comment可与on搭配） commentary（对书籍等的）评语，评注，评论；实况报道 eg:Stop shouting!I can't hear the football *commentary*. 希望对你有用。