

今日は欠席の生徒が三人います。
欠席の連絡は朝八時までにしてください。
欠席の理由を先生に説明しましたか。
"けっせきの(欠席の)" is in the lesson "School" (Level 10), along with 13 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.