Ключевые слова: academic, aged, algebra, answering, attendant, audience, backtoschool, caucasian, classmate, classroom, clever, college, consulting, conversation, course, discussing, education, equation, experienced, explaining, formula, girl, greyhair, group, groupmate, guy, highschool, knowledge, learner, lesson, man, mature, note, people, profession, professor, school, schoolwork, senior, student, study, talking, teacher, teenager, trigonometry, university,