Technicians can date paint from its chemical composition, for example, or X-ray a canvas to reveal what lies below the surface.

例如，技术人员可以通过其化学成分分析其创作日期，或者对一幅画做X光透视，揭示其表面下有什么。

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I'll cover this in more detail in the section on composition, below.

我将在下面有关组合的部分中对此进行更详细的讨论。

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If I'm sitting below the line here somewhere, so I'm sitting here. Some composition in the gas phase, a certain pressure.

如果我位于这条线以下的，某个位置，比如这里，给定的压强，给定的气体组分，很好。

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Phase II, planned for 2011, will identify both aquifers down to 3, 000 meters below the surface, study soil composition and aquifer replenishment, and prioritize areas for agricultural development.

UNESCO: launches initiative to identify groundwater and alleviate water shortages in Iraq | United Nations Educational, Scientific and Cultural Organization

Since cosmic radiation alters surface composition, Curiosity can drill into rock to extract pristine material from below.

CNN: Curiosity opening Martian frontier?