英文语法中插入句为简短的、具有完整意义的句子。常见的插入句如下: I think / hope / guess / know / believe / suppose, I am sure (我可以肯定地说), that is ( to say )(也就是说), it seems (看来是), as I see it (照我看来), what's more, what's worse, what is important / serious (重要 / 严重的是), I'm afraid (恐怕) , it is said (据说), as we all know (众所周知)等。