It often has to be that the only way you can raise money for a business is through a bank.

这通常造成了,只能通过银行进行商业筹资

耶鲁公开课 - 金融市场课程节选

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