The model divided GUI into four-layers: Windows framework layer, interface element layer, functional structure layer and running record layer.

模型将GUI分为窗口框架层、界面元素层、功能结构层和运行记录层四层。

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The second layer is that we record paths for files whenever possible (and it is nearly always possible).

第二层防御是尽可能地记录文件的路径（几乎总是可能）。

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The other is to examine in detail the archaeological record just above the charcoal layer.

另一种方法则是在木炭层上详细找寻考古学上的任何证据。

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The other is to examine in detail the archaeological record just above the charcoal layer.

ECONOMIST: Mass extinctions

The question is one of the most hotly contested in palaeontology and revolves around an apparent gap in the fossil record immediately prior to the K-T boundary - the distinct layer of geological sediments separating the Cretaceous and Tertiary periods, and associated with a massive asteroid impact and global extinction event.

BBC: Closing the 'three metre gap'