Why traffic lights are red, yellow and green？

为什么交通灯是红、黄、绿三种颜色的？

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Color four squares into red, yellow, blue or green.

给四个正方形涂色：红色、黄色、蓝色或绿色。

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Velázquez's 1653 portrait in oil of the Infanta Maria Marguerita hangs alongside Picasso's geometric riot of yellow, red and green of the same subject.

Velázquez 的1653年的 Infanta Maria Marguerita 油画肖像与毕加索的同一个主题的黄色、红色和绿色几何暴动挂在一起。

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Fortunato was beautiful in his silk suit made of many colors: yellow, green, purple and red.

VOA: special.2009.02.07

And I'm sure you can imagine that if you want to label onw protein green and one red and one yellow, now you can start looking at really complex biological processes.

我相信你们可以想象如果你,需要把一个蛋白质标记成绿色,一个标记红色，一个标记黄色，这样你就可以研究非常复杂的生物学过程。

麻省理工公开课 - 化学原理课程节选

Some are yellow, some are red, and some are green - does anybody know what this is?

一些是黄色,一些是红色,一些是绿色的,有人知道这是什么吗

耶鲁公开课 - 生物医学工程探索课程节选

The numbers flash red, yellow or green depending on whether the company is meeting its goals.

FORBES: LivingSocial To Overtake Groupon With $400M: LivingSocial Investor

Experiment with heirloom tomatoes yellow, green or red if you can find them.

NPR: Cranking Up Savory Sorbet

Beta carotene exists in the yellow, green and red pigmenting agents found in many fruits and vegetables.

CNN: Should I take beta carotene as a supplement?