Long time no see.

好久不见。

How long has it been?

（我们）已经多久（没见面了）？

I haven't seen you in a while.

我有一段时间没见过你了。

I haven't seen you lately. 

我最近都没见到你。

I haven't seen you in ages.

我有好几年没见过你了。

It's been a long time.

已经好长时间了。

It's been ages.

已经好几年了。

It's been a while.

有一段时间了。

I don't see you much these days.

这些天没怎么见你啊。

I haven't seen you around. 

最近没有在附近看到你。

How have you been?/How have you been doing?

最近过的怎么样？

What have you been doing?/What have you been up to?

最近在忙什么？

Dialogue1:

A: Long time no see. How have you been?

好久不见，你最近过的好吗？

B: Great, how about you?

很好，你呢？

Dialogue2:

A: Good morning, Mrs Jones. I haven't seen you around in a while. 

早上好，琼斯女士。我有一段时间没有见到你了。

B: I've been out of town for a couple of weeks. 

我有几个星期不在市里。

Dialogue3:

A: How have you been, it's been...What? Three years?

你最近过的怎么样？我们已经...什么？三年没见了？

B: It's been three years already? Wow, time flies. 

已经三年了？天哪，时间过的真快。

Dialogue4:

A: I don't see you around much these days.

这几天我都没怎么看到你。

B: Yeah, you're right. Since I got a girlfriend, I haven't had much free time. 

是的，因为我找了个女朋友，所以最近没有自由时间了。

Dialogue5:

A: How has your family been？

你家人最近还好吧？

B: They've been doing well. My little sister still asks about you. 

他们都挺好的。我的妹妹到现在还问起你呢。

Dialogue6:

A: Hi, Jenny. How's your son doing?

你好，珍妮，你儿子怎么样了？

B: He's doing fine, thanks. How about your little girl?

他挺好的，谢谢。你的女儿怎么样了？