Haven’t seen you for weeks.

幾周沒見到你了。

It’s been (such) a long time.

好久(好久)不見。

It’s been too long.

久別重逢后如何問候

太久沒見了。

Long time no see.

好久不見。

How long has it been?

我們多久沒見了？

It’s been ages since we last met.

自從我們上次見面已經過去許多年了。

Fancy meeting you here.

沒想到在這遇見你。

It’s always a pleasure to see you.

見到你總讓我很高興。

I’m so happy to see you again.

又見到你我太高興了。

You haven’t been around much lately, have you?

你最近沒怎么在這里露面，是不是？

How come I never see you?

我怎么一直都沒見到你？

What have you been up to all these years?

這么些年來你都在忙什么呢？

How’ve you been all these years？

這些年來過得如何？

Where have you been hiding?

你躲哪兒去了？

Hello stranger! Have you moved or something?

(好久不見)你好呀，你是搬走了還是怎么的？

注：hello stranger是對于認識卻很久沒見的人的幽默說法。