what do you call the student in charge of a specific subject

or this doesn't even exist in your country?? Is there any student who is entitled to help teachers ?? Besides monitor.. . . what do you call it?

In the US, a student helper is called a TA (teaching assistant), who would not be in the class. The TA is usually an older student that has already taken the class.

It seems that the way we are educated is totally different. We don't have counselor in our school, and some of the class mates are picked to be entitled to control other students. ( like leaders)
and there are many of them, each of them only takes the responsibility for one specific area.
but I don't know the English equivalent of those Chinese terms.

CharmYouIn china there is a student who takes charge of each subject

We don't have this situation in British schools.

Hi

I would say that the English equivalent is 'prefect'. They are not usually in charge of one subject, but they are chosen to act as leaders in their school class

http://dictionary.cambridge.org/dictionary/british/prefect_2

Dave

dave_anonI would say that the English equivalent is 'prefect'. They are not usually in charge of one subject, but they are chosen to act as leaders in their school class

Prefects usually have duties outside the classroom, not inside.

Hi

Yes, that's fair comment

In some contexts you could use 'monitor' or maybe 'mentor'

Dave

Thanks. Is there any other terms that can be used to refer a student with power? Is there a student union or student association?? Students there usually have the duty to check if other students go to sleep on time , if not they could tell the teacher to punish you.
Does student union or association exist in your country??

Hi

In some primary and secondary schools, with the agreement of the teachers, there might be a school council. The representatives from that would meet with teachers to discuss anything of concern to the students

In further and higher education, all students are entitled to join a Student Union and elect representatives to go to the school authority to present issues or ideas

In America, there are a student council and a class president in some schools. The positions are unofficial, and they have no power. It is mostly honorary and is meant to be a learning experience for the students involved. Some schools designate certain students as hall monitors, who are supposed to report bad behavior in the hallways, mostly in the lower grades. There is also the Safety Patrol, s