One day, while Giovani was looking out his window, he saw an old man in a black cape walking in the garden.

VOA: special.2009.05.23

So there are two electron configurations in the n equals one shell, if we follow according to the selection rules that we spelled out last day.

如果根据上次课,我们阐明的原子光谱选择定则，我们就会知道在n等于1的那一层,有两种电子图像构型。

麻省理工公开课 - 固态化学导论课程节选

One day he struck out three times in one game.

VOA: special.2009.10.25