The first signal did not include the color yellow for caution, but that was later added within a few years.
英
美
- 第一次信号中不包括用于“注意”的黄色，黄色是以后几年内后加的。
- 今日热词
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- 深远海浮式风电平台 - deep-sea floating wind power platform
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- 京雄高速公路 - Beijing-Xiongan expressway
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- 农业及相关产业增加值 - the added value of agriculture and related industries
