我不知道说什么好。

I don't know what to say.

《牛津词典》

“哇！你有一个大鼻子！”我感到很受伤，不知道说什么好。

"Man! You have one big nose!" I felt hurt and didn't know what to say.

youdao

医生望着盘子，不知道说什么好，他叫道：“啊，可怜的螃蟹。”

The doctor looked at the dish, had no idea what to say, and cried: "Ah, poor Crabb."

youdao

Now, I don't know how far back it goes but it must be that in ancient times some people would say, all right you're going to be doing more work or you're contributing more to this enterprise, we'll give you a bigger share of the profits.

我不知道这能追溯到什么时候,但在古时候肯定有人说,好吧,你比别人干得多,你对公司的贡献更大,我们会把收入的大头给你

耶鲁公开课 - 金融市场课程节选