

森の中に鹿が通った跡があります。
この跡は何の動物か分かりますか。
たき火の跡は、きれいに片付けてください。
"あと(跡)" is in the lesson "Camping 2" (Level 25), along with 9 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.