A lot of times we talk about these kind of distances either in nanometers or in angstroms so we can say this is 70 angstroms.

我们在讨论此类的距离时,很多都用到纳米和埃米的单位,所以它的波长是70埃米。

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So what we do is we pick an origin, call it zero, we put some markers there to measure distance, and we say this guy is sitting at 1,2,3,4,5.

我们现在选择一个原点,称其为零点,我们做一些标记来测量距离,这个点在五个单位长度的地方

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