This bond is polar, but again, as I alluded to earlier, because the carbon is centered in the tetrahedron, because of the sp3 hybridization, the molecule itself is symmetric and nonpolar.

这个键是非极性的，但是，我们断言过早，因为C是中心原子，由于sp3杂化，这个分子本身是非极性的且对称的。

麻省理工公开课 - 固态化学导论课程节选