Recently I had the honor to attend a class which was given by Ms. Tang . It was very impressive.  Low profile in form, yet highly efficient in result.  By group cooperation  role exchange , self-evaluation, situational simulation, each student has enough opportunities  to practice in groups which is so crucial in language learning. we often say we should return the time to students. The teacher should say as little as possible in class.  It’s easy to say but difficult to do . Teaches have got used to emphasizing here and there for fearing that the students will not understand. Actually the time that students make the rapidest progress is when the students practice by themselves. From that sense, the class has been very successful