Переделать в косвенную речь how long does a pupil stay at primary school? what age do children enter the secondary school? what kind of school is a comprehensive school? are there schools where children have to have entranse exams? надо

They asked me how long a pupil stayed at primary school.
They asked me at what age children entered the secondary school.
They asked me what kind of school a comprehensive school was.
They asked me if there were schools where children had to have entrance exams.