then what you have is a carbon in the middle with three hydrogens around it, and then it can only be bonded to one other thing.

那么你就会有一个碳原子在中心,三个氢原子围绕着它，那么它只能再和一个原子成键。

麻省理工公开课 - 化学原理课程节选

I think of Square as a platform that's going to build an ecosystem around it.

我觉得Square是一个很好的平台,可以围绕它打造一个很好的生态系统。

斯坦福公开课 - Twitter之父Jack.Dorsey演讲：好奇和灵感的力量课程节选