Могут ли школьники иметь работу? Дописать предложения.On the one хэнд .....

On the one хэнд school students can have a work, on the other hand they must learn.
Firstly, they can lose their knowledge.
Secondly, they can't mix work and study.
Finally, they can't get certificate of the ending of study.
Besides, their parents will not be satisfied.
Moreover, pupils will be tired, because they work all the night, because of they go to study sleepy.
They can work since 11 p.m. 
As a result their success will be bad either work, or study.
However a lot of school students begin to work.
So, everybody chooses their way.