I think this is taken about two years after they discovered the fourth quantum number.

这张照片拍摄于他们发现,第四个量子数的两年后。

麻省理工公开课 - 化学原理课程节选

And this is one of them where they compare babies looking at this versus this.

这是其中的一个研究,心理学家们在比较,婴儿对这两张照片的注视情况

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