1. The occurrence of overpopulation in China.
2. Why China’s overpopulation occurs.
3. The implementation of birth control in China.

A．the couple’s earning ability
B．the relative balance between the benefits and costs of marriage
C．how much possessions the couple have before marriage
D．a network of social and legal support

A．visit Mrs. Left and Mrs. Right
B．roll up the curtains
C．try to work out his plans for the day
D．make Mrs. Left argue with Mrs. Right