The engineers face a difficult challenge.

工程师们面临一个困难的挑战。

youdao

This challenge is extremely difficult challenge.

这个挑战极其困难。

youdao

Bridging the two is a difficult challenge for many industries.

对于许多行业来说将其两者连接起来是很大的挑战。

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And he is praising four committees in Congress for agreeing on what he calls "a difficult and complex challenge."

VOA: standard.2009.08.08

And scientists have been working on this for years and there's been progress, but it's still a very difficult challenge.

科学家们对此已经研究很久了,并取得了进展,但仍有很大挑战

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That's a very difficult challenge in the Senate right now. It's not looking very good these days,

目前这在参议院是很大的挑战。现今的形势看上去不容乐观。

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And restoring health in the housing market after its dramatic collapse remains a difficult challenge.

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Understanding APTs and blocking potential attack vectors before they occur is a difficult challenge.

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That, of course, is a difficult challenge for any self-respecting bureaucrat, let alone politician.

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