A. currently wealth flows from old generation to younger generation
B. traditionally wealth flows from younger generation to old generation
C. with the increasingly big population of over 50, the trend arises that wealth flows from younger generation to old generation
D. with more and more people of over 50, all traditions have been reversed

A. let their children read any books they like to
B. not let their children see any films they like to
C. not let their children read any books without first checking their contents
D. let their children see the films with their first checking