

十二月は忙しいですね。
十二月二十五日はクリスマスです。
十二月に雪が降りますか?
"じゅうにがつ(十二月)" is in the lesson "Months and days" (Level 7), along with 18 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.