The researchers haven't nailed down the exact reasons behind this trend.

研究人员尚未弄清这一趋势背后的确切原因。

Did try nailing a couple of the boards down.

我把几块板子钉下去了。

I'm just having problems nailing down a background source.

我只是在定下背景起源时碰到了一点点问题。

It's as high as I could nail down so far.

目前是我能找到的最好的线人了。

To nail down the potential environmental influences, researchers focused on the classroom.

为了明确可能存在的环境影响，研究人员将研究重点放在了教室这个特殊场所上。

Others prefer to look for connections between ideas rather than nailing down facts.

另一些人则更喜欢寻找观点之间的联系，而不是弄清真相。

And we've yet to nail down the precise mechanisms behind mucosal destruction.

我们还不能明确粘膜损伤具体的机制。

Finally, after all these centuries, the astronomical unit was nailed down.

几个世纪后，这个天文单位终于被确定下来。

Scientists have not nailed down one single answer, but there are a few possibilities.

科学家们还没有确定一个单一的答案，但有几种可能性。

So without those specific details nailed down, why would the White House accept the invitation?

在这些具体细节都没有确定的情况下，为什么白宫会接受这一会面邀请？

You know, I don't think you ever nail anything down right here. It's always moving.

我认为你们没有弄清事情的发展，情况一直在不断变化。

It's hard for us to nail down with any sort of granularity exactly what's happening on the ground.

我们很难理解地面上究竟发生了什么。

Based on this information, the researchers nailed down when and where the next flu outbreaks were likely to occur.

但是基于这些信息，研究人员确定了下一场流感爆发可能发生的时间和地点。

Hopefully the show will conclude with the actual wedding itself or at least get it fully nailed down for us.

希望这部剧能以他们的婚礼结束，或者至少能让我们确定他们已经板上钉钉了。

So, U.S. negotiators will be looking to nail that down.

因此，美国谈判代表将寻求确定这一点。

But it's hard to really nail down the definition.

但很难真正确定定义。

Okay. - Perfectly, nailed down and everything.

好的 - 完美的放好 把所有的都弄好。

This is where his multi-billion-dollar valuation is difficult to nail down.

这就是他数十亿美元的估值难以确定的地方。

When Pa had nailed down two slabs, he got up on them.

当爸爸钉下两块石板后，他就爬上去。

" That'll really be able to nail down more about the origin" .

“这将真正能够确定更多关于起源的信息” 。