The sperm - say this is the one sperm cell that's able to inject its DNA into the egg, well then this cell has a polarity.

假设某个精子细胞,成功向卵子注入了自己的DNA,那这个细胞就有了极性

耶鲁公开课 - 生物医学工程探索课程节选

The magnet creates a field which changes the polarity of a tiny, tiny portion of the metal particles which coat each platter's surface.

这个磁体创建一个,能改变覆盖在,磁盘表面小金属粒子的磁极。

哈佛公开课 - 计算机科学课程节选

Different kinds of polarity form, there's a head, and there's a tail, there's a back, there's a front, there's a left side and there's a right side.

不同的极性开始形成,有头端,也有尾端,有后面,也有前面,有左侧,也有右侧

耶鲁公开课 - 生物医学工程探索课程节选