1. 研究   mark   examination   lesson   study   Hint Half-n-half Clue   2. 学会   examination   answer   learn   lesson   Half-n-half Clue   3. 标记   teach   mark   lesson   write   Half-n-half Clue   4. 更正   correction   teaching   teach   answer   Half-n-half Clue   5. 问题   correction   write   question   study   Half-n-half Clue   6. 教训   teach   teaching   lesson   homework   Half-n-half Clue   7. 写   write   correction   question   examination   Half-n-half Clue