A．Now, there are no wars and people live in a peaceful world.B．More children can live to their adulthood and have their own children.C．People live longer now than in the past.D．People immunize many fatal diseases of which many people died.
A．Now, there are no wars and people live in a peaceful world.
B．More children can live to their adulthood and have their own children.
C．People live longer now than in the past.
D．People immunize many fatal diseases of which many people died.