But when you pass a parameter say, a list, you didn't think that you were not only passing the list, you were also passing the functions that operate on the list. In fact you are.

你不会认为你输入的不仅仅是链表，你还传递了处理链表的函数,实际上你正是这么做的,这往往不重要。

麻省理工公开课 - 计算机科学及编程导论课程节选

It means anybody using that little function get float doesn't have to worry about what's inside of it. So for example, I decide I want to change the message I print out, I don't have to change the function, I just pass in a different parameter.

这代表着用这个方法去获得浮点数,的任何人都不用担心具体的实现了,例如，如果我想改变下,显示的信息的话，我不必去改变方法，我传个不同的参数就可以了。

麻省理工公开课 - 计算机科学及编程导论课程节选

In the options parameter of this new method, pass nil to access Twitter and Weibo accounts.

ENGADGET: Apple seeds iOS 6 beta 4 to developers: here's the changelog