我喜欢一个人很久了用英语怎么说

"I have liked someone for a long time" 可以说成 "I have had a crush on someone for a long time" 或 "I have been interested in someone for a long time"。

"Crush" 是一个英文单词，它的意思是迷恋、爱慕。来源于17世纪，最初是指破碎的东西，后来引申为对某人的喜爱。例如：

I have had a crush on her since the first day of school.
He's had a crush on her for years, but he's too shy to tell her.

"Interest" 是另一个英文单词，它的意思是兴趣、爱好。来源于14世纪，最初是指财政利益，后来引申为对某事物的关注。例如：

I've been interested in him for a while now.
She has always been interested in art.