当一个用户在使用一个同步源的时候，它会标记会不可用。

A source is marked as unavailable, while it is accessed by another user.

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当一个用户第一次登录到站点时，他便建立一个惟一的ID。

When a user logs onto the site for the first time, he establishes a unique ID.

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当一个用户发出命令时，该服务员就会消失，然后返回命令。

When a customer places an order, the waiter goes off and returns it.

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So, ask yourself frankly especially when it comes to designing your own tools and your own programs whether it's for real users to use, whether it's for your research group to use in some other field, you know, where do you even begin?

坦白讲，问一问你们自己,当你设计一个工具，一个程序时,它是否是为真实用户使用的，还是为在其他领域的,研究团队使用的，你们懂的，你从哪里开始？

哈佛公开课 - 计算机科学课程节选

So when you have a function called GetString, -- that means it's going to get a string from the user -- -- prompt the user for a string -- whereas printf is literally going to print it, not to paper, but to the screen.

所以当你有一个叫做GetSting的函数，它的意思是从用户那获得一个字符串-,提示用户输入一个字符串-,然而printf的确是用来打印的，不是在纸上，而是在屏幕上。

哈佛公开课 - 计算机科学课程节选