Some of these NASA workers claim efforts to redeploy their skills in other areas come too late with just four shuttle missions remaining.

VOA: standard.2010.03.18

If I now hybridize these, if I take these and I make four symmetric, now, these are just the sp3 orbitals.

如果我将他们杂化，然后形成4个对称的轨道，这就是sp3轨道。

麻省理工公开课 - 固态化学导论课程节选