Because you won't want to do everything from scratch yourself, you want to be able to look at what is being created by somebody else and understand what is inside of there, whether it works correctly and how you can build on it This is one of the few places where plagiarism is an OK thing.

因为你们不会想无论做什么事情,都由你们自己亲自上阵，你们希望有能力读懂,别人创造的语言,并了解其中的内涵，运转的正确性和如何在其基础之上继续发展,这是为数不多的,合理的作弊行为之一。

麻省理工公开课 - 计算机科学及编程导论课程节选