问题详情

What do happily married couples have to do to get the protective effect that a satisfactory relationship has on their hearts？
A．To avoid quarrelling with one"s partner.
B．To feel satisfied with their present way of life.
C．To spend more time together.
D．To keep away from unhealthy lifestyles.请帮忙给出正确答案和分析，谢谢！