It was the largest and most difficult structure of its kind ever built when work started in nineteen thirty-one.

VOA: special.2009.08.12

But it's a difficult claim because even as Milton makes this claim, he manages to undermine its force.

但这是困难的，因为即便是弥尔顿做出了这一宣告，他也打算降低它所蕴含的威力。

耶鲁公开课 - 弥尔顿课程节选

And we'll look back maybe and see how that difficult text would've looked in its original context.

我们会倒回去看看这一不同文本,在其原背景下是什么样的。

耶鲁公开课 - 新约课程节选

In the middle of such a slow motion explosion, its difficult to know which way to run.

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Of course, the story of our nation is not without its difficult chapters.

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And according to Huillard, Europe must push through its difficult times by accelerating transport investment to jump start economic growth.

CNN: VINCI boss to Europe: Build and growth will come