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blue; azure
green
green light (traffic)
immature; unripe; young
black (horse coat color)
blue 5-point card
空の青がきれいだなあ。
The blue of the sky is so beautiful.
青が美しい草原を歩く。
I walk across a green and beautiful meadow.
信号が青に変わったら渡ってください。
Please cross when the light turns green.