You're joking, right?

你在开玩笑吧？

You've got to be joking./You're kidding.

你肯定是在开玩笑吧

I was completely surprised.

我真是大吃一惊

The news came out of nowhere.

这条新闻完全是无中生有

What a surprise.

真是意想不到

What a shock.

真是令人震惊

I can't believe it.

我不相信

That's incredible.

真是令人难以置信

Dialogue1:

A: I've got some good news to share with you. I just found out that I'm getting that promotion that I've always wanted.

我有个好消息要告诉你。我刚刚知道，我终于要如愿以偿获得晋升了。

B: Really? That's wonderful.

真的吗？这可是太好了。

Dialogue2:

A: I was completely surprised when she said she wanted a divorce.

当她说她要离婚的时候，我感到很惊讶。

B: You must have been in shock. Let me know if there is anything I can do for you.

你肯定是吓蒙了，要是有什么我能帮上忙的话，一定要告诉我。