And it's impossible to really nail it down because we all have different goals in life.

而这个值是不可能真正固定下来，因为我们都有不同的生活目标。

youdao

It would be useful if you could nail down the source of this tension.

如果你能弄清这种紧张情绪的根源，会是有用的。

《柯林斯英汉双解大词典》

The latter is characterized by the inability to nail down requirements up front, making it necessary to continually adapt and re-estimate as a project progresses.

后者的特征是没有事先明确了解需求的能力，因而需要随项目的进展不断地调整适应和重新评估。

youdao

It took three more tests, including a lung-tissue biopsy, to nail it down as TB.

WSJ: TB's Global Resurgence Amplifies U.S. Risk

So I'm just trying to nail it down.

WHITEHOUSE: Press Briefing

Finally, there's the prospect of Microsoft pulling in News Corp. into the fray to help it nail down Yahoo!

FORBES: Magazine Article