If I knew then既然有then为什么是knew?

If I Knew Then 歌词 If I knew then what I know 求If I knew then 的伴奏 If I knew then what I know now!求翻译 If only i knew then what i know now If I Knew Then (What I Know Now) 歌词 If I Knew Then Lady Antebellum唱的,中文翻译,谢谢. 翻译 后街的if i knew then 的歌词 If I Knew Then What I Know Now (Duet With Gladys Knight) (Al If only i knew then what i konw now.这句怎么解析 I knew then that even if he never broke the world record,he 急求后街男孩《if I knew then》的伴奏带~~~