①
I cannot have this conversation again.
我不想再聊这个了。

I already told you how I feel about you going to Europe by yourself. I cannot have this conversation again.
我已经告诉过你我对于你独自去欧洲的想法了。我不想再聊这个话题了。

We argued for a whole day about this. I cannot have this conversation again.
关于这件事情我们争论了一整天。我不想再继续这个话题了。

②
I don't want to talk about it.
我不想说这个。

Look, I don't want to talk about it. She's with somebody else now and I don't care.
听着，我不想聊这个。她现在跟了别人，我不在乎。

③
Drop it/leave it
别说了

He obviously doesn't want to answer you so just drop it.
很明显的，他不想回答你的问题。所以，别说了。

She already told you she doesn't like you. Let's leave it at that.
她已经告诉你她不喜欢你了。这事就到这吧。

④
The matter is closed.
事情就到这为止

The board won't approve of the buyout. They'll vote against it this afternoon. The matter is closed.
董事会不会同意这次收购的。下午他们会就此事投反对票。事情就到这。

⑤
There'll be no more discussion on it.
没什么可商量的了

I told you what you need to do so either you do it or leave. There'll be no more discussion on it.
我已经告诉你你需要做什么了。所以要么照做，要么离开。没什么可商量的了。

⑥
That's final.
事情到此为止

Your mom and I don't approve of you dropping out of school to become a musician and that's final.
你妈和我不同意你退学去做音乐。事情到此为止。

I won't buy you X-Box. That's final.
我不会给你买X-Boxd ,事情到此为止。

You can't go to the bar tonight. That's final.
你今天晚上不能去酒吧，没有商量的余地。