首先我们必须找出问题所在。

First of all we must identify the problem areas.

《牛津词典》

在 “激战阶段” 进行的更改一开始好像没有危害，但当它开始导致问题时，要找出问题所在就仿佛是大海捞针。

Change made in the "heat of battle" might seem innocuous at first, but when it begins to cause problems, you are left to find the needle in a haystack.

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当飞机从空中坠落，比如2009年6月30日的一架也门客机在飞往印度洋的科摩罗群岛时那样，黑匣子是找出问题所在的最佳选择。

When planes fall from the sky, as a Yemeni airliner did on its way to Comoros Islands in the India ocean June 30, 2009, the black box is the best bet for identifying what went wrong.

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