观看电视，凭你手中的遥控板便可调频、调色、调声，而频、色、声的变化都在电视机上，它是主体，你只起“调”的作用，即主导。 　　课堂上，如将在座的同学看作电视机这一主体，教师便是手握“遥控板”的主导。 　　毫不松手、漫无目的地调度，一场精彩的电视节目便难以欣赏 Watch TV. With the remote control in your hands, you can adjust, tone, and tune the sound. The changes in frequency, color, and sound are all on the TV. It is the main body. You only play the role of “adjustment”, that is, you dominate. In the classroom, if the classmates are regarded as the main body of the television, the teacher is holding the “remote control board”. Undaunted, goalless scheduling, a wonderful TV program is difficult to appreciate