Okay, so we just glimpsed this at the end last time.

上节课结束时我们瞄了一眼这张图
This is a crystal structure of a complicated molecule

这是一个复杂分子的晶体结构
that was performed by these same Swiss folks that we've talked about,

这张图看起来很像我们提到过的瑞士叉子
and notice how very precise it is.

这张图的精度非常高
The bond distances between atoms are reported to

据报道图中的键长的精度
±1/2000th of an angstrom.

达到了±1/2000个埃
The bonds are like one and a half angstroms.

一个化学键的长度大约有1.5埃
So it's like a part in a thousand,

所以他们精确到了千分之一
is the precision to which the positions of the atoms is known.

也就是我们所知的原子位置的精度
But those positions are average positions,

但这些原子的位置只是个平均值
because the atoms are constantly in motion, vibrating.

因为原子是不停运动的它们会振动