about arguments pls !!!!!!!!!!

Is this the topic of a debate, or an argumentative essay?
May I ask what is your stance?!?! XD

I will assume that you are supporting this stance.
You may focus on these:

1) Students will do more exercise and be physically healthier.
Reason:
Students in HK, a city which puts high emphasis on academic results,
rarely do any exercise because they spend most of their time on revising.

Problem:
And little exercise will lead to health issues, such as obesity...(examples)

Impact of having compulsory classes:
they will do more exercise, so they have better health
which is beneficial to students in long-term(prevent disease, control weight)

This is a common framework for an argument
Elaborate more by yourself, add examples, use persuasive words,
here are other points...

2) It improves mood ---> relieve pressure and help to combat depression,
students feel happier and relaxed when enjoying sports
as their weight is controlled, it also boost self-esteem and confidence
because they feel better about their appearance ( X obesity)

3) Improve learning efficiency --> exercise helps prevent disease
which prevent them from being absent and skipping lessons
also, exercise can train student's concentration
thus they pay more attention in class

4) It helps student to form a healthy habit and encourages students to
take up sports as interests----> healthy + all-rounded development...

Rebuttal:
- emphasise the importance of health which can't be brought by money
- asking them to do exercise on their own is doomed to fail
because students are still young and don't understand the importance of it.
we need to be more forceful in asking them to do exercise.
- morning sessions won't spend much time and won't hinder studies

Well, for the rest, think yourself...elaborate and give examples.
I hope this helps :)

Sorry I don't understand your question