要不然他还会在教书，因为他的心仍然在课堂上和他的学生们在一起。 Otherwise he would still be teaching, because his heart and soul were still in the classroom with his students.
老师在这类课堂活动中起着十分积极的作用。 The teacher plays a very active part in this type of classroom activity.
研究计划一个学生或一组学生执行以使用、阐明或补遗课堂作业的大量任务 An extensive task undertaken by a student or group of students to apply, illustrate, or supplement classroom lessons.
