What time does your school?这是一个病句.不过可以猜得出是在问：你们几点上课?
根据实际情况,可回答：It starts at 8 o'clock.或者 It begins at 8 o'clock.
完整的句子应该是加上start或者begin：
What time does your school start?
What time does your school begin?