1、可以用unique这个单词或者是the only one。
2、但是还有一种更加地道更加有味道的表达：one of a kind;If you refer to someone or something as one of a kind, you mean that there is nobody or nothing else like them.如果你用这个表达来形容某人或者某物，你的意思就是在说他们是独一无二的，特别的。
3、例句：
This is a one of a kind opportunity—you have to take it!
这是一次非常罕见的机会，你一定要抓住！
I dont know how well ever replace May after she leaves. Shes really one of a kind.
我们不知道梅离开之后谁能取代她，她是独一无二的。