Rails是一种开放源码的Ruby框架，它用来开发以数据库作为后端的Web应用程序。

Rails is an open source Ruby framework for developing database-backed Web applications.

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如果你是一名开发人员，你需要一些优秀的Web开发应用程序，以帮助你完成工作。

If you're a developer, you need a good set of web development apps to help you get the job done.

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最近巴西和美国的科学家开发出一种简易快速检测钞票表面以鉴别真假的技术。

A simple and fast technique to examine the surface of banknotes and identify counterfeits has been developed by scientists in Brazil and the US.

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Not everybody had to be involved in creating food, and so that gave people more time to trade, to develop other products, to be involved in non-food pursuits and many, many more things.

不需要所有人都忙于制造食物,因此人们有空进行贸易,开发其它产品,以追求其他更多,而不单单是食品

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选