How can Milton know that he was really and truly called by God to be a great poet until he writes something - it's not a bad question - until he has something actually to show for his talent?

弥尔顿怎么知道他是不是真的被,上帝选中了去做一个伟大的诗人,除非他真的创作出点儿什么--这是一个不坏的问题,-直到他真有可以证明自己才能的作品？

耶鲁公开课 - 弥尔顿课程节选

If you want to make sure both conditions are true and they both have to be true for any code to be executed, use ampersand ampersand.

如果你想保证两个条件都成立,或者它们两个都必须为真值，才能执行一些代码，那就使用“&&“

哈佛公开课 - 计算机科学课程节选