

庭のくさがずいぶん伸びましたね。
くさの上に座りましょう。
公園のくさに入らないでください。
"くさ(草)" is in the lesson "Plants" (Level 29), 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.