The danger is likely to continue, they say, until the waves reach an inland area of hard rock which will not be eaten as limestone is.

他们说，这种危险可能会持续下去，直到海浪到达内陆坚硬的岩石区域，这些地方的岩石不会像石灰岩那样受到侵蚀。

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Back in the 1900s, some stop signs were yellow because it was too hard to see a red sign in a poorly lit area.

早在20世纪初，一些停车标志是黄色的，因为在光线不好的地方很难看到红色标志。

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Then,a hard cast may be put around the area of the break to hold the bone in place while it heals.

VOA: special.2009.02.04

I think that it makes it hard for that particular area of scientific research to go forward.

我想在这方面的科学研究很难推进。

生物克隆是热点问题 - SpeakingMax英语口语达人

They seem like the hard rock maple trees often found in that area, nothing can make them move.

VOA: special.2009.03.07

And he said the planned hard surface area had been reduced by 25%, but in other respects the application remained the same as that submitted in 2011.

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It's not a hard hat area for nothing.

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It's hard to find area stops large enough to accommodate, say, 80 West Point cadets.

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