

夏休みの間に国へ帰ります。
授業の間は携帯を使わないでください。
旅行の間、猫はどうするの?
"のあいだ(の間)" is in the lesson "When" (Level 42), 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.