小明老爱问为什么，老爱打破沙锅问到底。

Xiaoming always asks why and he'll never be satisfied until he knows everything.

《新英汉大辞典》

国会需要问问到底出了什么差错。

Congress needs to ask what went wrong.

youdao

很幸运，米勒先生没有对这个问题打破沙锅问到底。

Fortunately, Mr Miller does not press that question too hard.

youdao

Thermodynamics is asking you, what work does this thing do on the surroundings or the surroundings do on the system?

热力学在问你们，到底是系统对环境做功,还是环境对系统做功？

麻省理工公开课 - 热力学与动力学课程节选

So we have to assume that the occasion for this poem is some kind of question posed by John Milton, Sr., a question like, "To what end am I supporting you, Son?

我们可以假定这个诗的起因是,老约翰弥尔顿问小弥尔顿，“我到底为什么要资助你，儿子？“

耶鲁公开课 - 弥尔顿课程节选

Then you might ask, why in the world do companies issue stock dividends anyway, what's the point?

你可能要问,那公司发放股票股利到底是为了什么呢,意义何在

耶鲁公开课 - 金融市场课程节选