

今日は家の中で遊びましょう。
電車の中で本を読みます。
果物の中で何がいちばん好きですか。
"のなかで(の中で)" is in the lesson "Adverbs 1" (Level 23), along with 15 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.