A subroutine is a part of a program that can be re-used , just like movable type .

一个子程序就是程序中可以被重用的部分，就像印刷术中的活字一样。

The idea , says mr gates , has always been to apply this principle of a subroutine more broadly .

比尔盖茨认为，模块化一直以来就是将子程序的原理应用到更广泛的领域。