is the 加名詞還是形容詞

都可以

Sb. is the＋形容詞最高階＋名詞 that I have ever seen (known/heard/had) 某人是我見過的（知道的／聽過的／遇見）最……的人

如:

She is the loveliest girl that I have ever seen.她是我見過的最可愛的女孩。

John is the cleverest student that I have ever known.湯姆是我知道是最聰明的學生。

She is the most interesting person that I have ever heard.她是我聽過的最有趣的人。

He is the most generous man that I have ever met.他是我遇見過的最慷慨的人

the是特指某物的冠詞，放在句首

如：The ball is behind me.有的時候在一些國名全稱之前，如：the U.S.A.