我要告诉你一件你意想不到的事！

I have a surprise for you!

《牛津词典》

我要告诉你一件意想不到的事：我们要搬到瑞士去！

I have a surprise for you: We are moving to Switzerland!

《柯林斯英汉双解大词典》

在我离开这个世界之前，我必须告诉你一件在我心里藏了二十多年的事。

Before I leave this world, I have to tell you one thing that has been hidden in my heart for over twenty years.

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But I do want to tell you this one thing.

但我想告诉你一件事。

耶鲁公开课 - 死亡课程节选

Two things. One is to always say that you love him.

两件事。一是总是告诉孩子你爱他。

要成为好爸爸 - SpeakingMax英语口语达人