它提供了标准化的方式用于执行各种任务，如表单验证、计算和条件输出。

It provides a standardized way to perform tasks like form validation, calculations, and conditional output.

youdao

为分支输出构建条件。

Build conditions for branch outputs.

youdao

当活动执行时，它将正好产生一个输入条件的所有输出。

When an activity executes, it produces all outputs of exactly one output criterion.

youdao

Computing square root. I'm going to capture it in a piece of code, I'm going to be able to refer to it by a name, and I'm going to suppress the details, meaning inside of that computation, you don't need to know what it does. You just need to know, if I give it the right kind of input, it'll give me back an input that satisfies the contract that I set up.

比如计算平方根,我会用一段代码来说明,我将给它命名,并且忽略细节,意思就是在这一段计算过程中,你不用知道它做了什么，你只需知道，如果我进行了正确的输入,它将会给我符合条件的输出。

麻省理工公开课 - 计算机科学及编程导论课程节选