Teacher Xu, Please Take Care of the Reckless Students in Your Class

The students in this class either go to sleep, play with mobile phones, or go out to play ball or games during class time; they do not go home at night;
"Which class are you from? It's too much to do whatever you want!"
"Mr. Xu's class, do you have any comments?"
"No no no! It turned out to be Teacher Xu's student, you continue! Excuse me!"
A class of 20 people, under the guidance of Xu Heng, ranks in the top [-] in the province. In addition to academics, they are all present in scientific research, computer science, Chinese studies, and international competitions.
"Mr. Xu, we have to keep a low profile and give other teachers face? They will, we will, they won't, we will!"
"The country invited us to participate in the competition! Without Teacher Xu leading the team, we will not go!"
"Qingbei is here to dig me! It's useless for my parents to beg me, unless Teacher Xu nods his head!"
"It's not Mr. Xu's question, it's really easy! Everyone submits it together..