Long time no see.
It's been so long.
Haven’t seen you for long
Have not seen you for a long time
[Long Time No See.本來是錯誤的文法 但是現在卻變成正確的口語說法
原來是所謂的Chinglish中式英文 (好久=long time, 不=no, 看見=see)]
I have not seen you for a long time. (這是我在課堂上講得)
It's been a long time. How are you doing?
It has been a long time. How's everything?
It's been such a long time since the last time I saw you.
It's been a long time since I last saw you.