I'll be a monkey's uncle!

US /aɪl bi ə ˈmʌŋ.kiz ˈʌŋ.kl̩/
UK /aɪl bi ə ˈmʌŋ.kiz ˈʌŋ.kl̩/
"I'll be a monkey's uncle!" picture
1.

我真是太惊讶了, 真是活见鬼了

an exclamation of surprise, disbelief, or astonishment

:
You won the lottery? Well, I'll be a monkey's uncle!
你中彩票了?哇,我真是太惊讶了
He actually finished the marathon. I'll be a monkey's uncle!
他竟然跑完了马拉松。我真是太惊讶了