A．Helping them learn more knowledge．
B．Restraining them from engaging in criminal activity．
C．Tracing them when they escape．
D．Taking care of their children．
A．Enemies exist in everyone's life．
B．Humble people have fewer enemies．
C．It is terrible to have enemies．
D．Generous people are popular．
A．Something you have read．
B．Something you have experienced．
C．Something you have heard．
D．Something you have imagined．