First, you can drink water. Of course, drinking less water is useless. If you want to drink more water, you will feel sleepy. You can try if you don't believe me. Students who don't want to drink more water can prepare some refreshing drinks in advance, such as coffee and functional drinks. Generally, a drink in class in the morning can refresh you all day.
Second, you can always keep some essential balm, cooling oil, Eight Immortals Tube, etc. And apply wind oil essence and cool oil to face, temples and nearby people to instantly eliminate drowsiness and immediately refresh themselves. There is also the Eight Immortals Tube, which is also a common refreshing tool that everyone is familiar with. It is helpful to clear your head from time to time, but remember to be moderate, otherwise this kind of thing is very strong and will affect other students.
Third, stand up and listen to the class. There is nothing to be ashamed of. This is the most useful move for your own study. At first, the teacher said this method, and I am still deeply impressed. If you are too tall and afraid of blocking the students behind you, you can also stand in the last row of the class and listen to the class. Of course, the teacher punishes you not because you are sleepy, but to improve your efficiency and prevent you from being sleepy in class.
Fourth, you can exercise your muscles or pick up things. Sometimes, if you stay in class for too long, you will feel sleepy. Throw your pen or eraser under the table, and then lower your head to pick things up. It is best to pause for 30 seconds to concentrate the blood in the head, which will help to eliminate drowsiness, or get up and exercise properly without affecting other students.
Finally, I want to say, the most important thing is that I hope everyone will go to bed early the night before, ensure a good sleep quality and reduce staying up late, so that it is not easy to get sleepy and unclear in class, which solves the problem from the root.