

山の空気はおいしいです。
窓を開けて、空気を入れましょう。
この町は空気がきれいじゃないですね。
"くうき(空気)" is in the lesson "Nature" (Level 38), along with 11 other useful words. LinDuo has 180 topic lessons like this one, 2,379 words in total. Every word has an illustration, a transcription and pronunciation in a female and a male voice. Just 10–15 minutes a day is enough to learn them all. Free, and works offline.