赤い

In a sentence

• この赤い花はとても美しいです。

  This red flower is very beautiful.

  Here, '赤い' ('akai') describes the flower's color, emphasizing its beautiful appearance.

• 彼は赤い車を買いました。

  He bought a red car.

  In this sentence, '赤い' ('akai') is used to modify the noun '車' ('kuruma'), specifying its color as red.

• 夕焼けが空を赤く染めました。

  The sunset dyed the sky red.

  Here, '赤い' is transformed into '赤く' ('akaku') as an adverb describing how the sky was dyed by the sunset.