Stumped [stʌmpt]
把某人難住

不知道怎么解決問題/如何做某事
不知怎么回答某個問題/感到迷惑

Question 42 has me a stumped. I don't know what the answer could be.
42題把我難住了。我不知道答案會是什么。

We've been stumped all day on how to do the client's new marketing campaign.
如何進行客戶新一輪的市場營銷難了我們一整天。

Don't have a clue
毫無頭緒

have no idea

I don't have a clue on what you want me to do. You say you want me to come over then you say you hate me.
我對于你想讓我做什么毫無頭緒。你讓我來，然后又說你恨我。

We have no clue how this could happened.
我們也不確定這事兒怎么就發(fā)生了。

I have no idea how this could happened.
我完全不明白這事怎么發(fā)生的。

At a loss
很迷茫/不確定

We are at a loss for how this could have happened. There's no explanation.
我們也不確定這事兒怎么就發(fā)生了。一個解釋都沒有。

At a loss for words
太驚訝以致于不知道說什么

have no words

So you're telling me she has a dog and a cat in her apartment, but at the same time she says she hates animals. I'm at a loss for words.
所以你是說她家里有一貓一狗，但同時她又說她討厭動物。我無語了。

Left speechless
無語，驚呆

She left the room speechless when she punched Gary in the mouth.
當她對著Gary的嘴打完一拳之后，屋里人都驚呆了。