还记得，每次我们有两个电子被共用，我们就有了一个单键。

Remember, every time we have two electrons that are being Shared, that's a single bond.

youdao

因为存在当有些项目没有被加亮的情况，不推荐在菜单键下面放置有前后关系的、针对项目的动作。

Since there are cases when items have no highlight, it's not recommended to place contextual, item-specific actions under the menu key.

youdao

Remember, every time we have two electrons that are being shared, that's a single bond.

还记得，每次我们有两个电子被共用，我们就有了一个单键。

麻省理工公开课 - 化学原理课程节选

So it looks a lot less messy if we just draw our Lewis structure like this for h c n, where we have h bonded to c triple bonded to n, and then a lone pair on the nitrogen there.

这看起来整洁了不少,如果我们把氰化氢的路易斯结构画成这样的话，这样我们就有氢与碳之间的单键和碳与氮之间三键，然后还有一对孤对电子在氮这里。

麻省理工公开课 - 化学原理课程节选

So if we have a single bond here, would you consider that a sigma bond or a pi bond?

如果这里有个单键，你觉得这是sigma键还是π键？

麻省理工公开课 - 化学原理课程节选