(i) Who does ‘they’ refer to?
‘They’ refers to the children in the old kind of school that Tommy describes.
(ii) What does ‘regular’ mean here?
‘Regular’ here means a mechanical or programmed teacher like Margie and Tommy have, not a human teacher.
(iii) What is it contrasted with?
It is contrasted with the mechanical teachers of Margie and Tommy, which are machines that teach children at home instead of a human teacher in a classroom.