In fact, many people will have this problem. The main problem is that the teacher may not be very exciting when listening to the class, or he doesn't like the content of the class. At this time, when he was giving lectures, he was easily sleepy, and the more sleepy he was, the more he didn't understand, the more he didn't want to listen, and he was also sleepy during the meeting, because all the contents of the meeting had little to do with Otawa himself. The so-called content of the meeting is mostly discussed by everyone. For his own sake, I feel sleepy myself. The above two reasons are the reasons for being sleepy. I hope I will do it again. Try not to get sleepy when I am sleepy. Although it is of little use to me, I'd better listen to it, which is still helpful to me.