A．Estrogen. B．The hormones of pregnancy. C．More exercise. D．Taking care of children.
单项选择题7（）
A．before B．besides C．with D．through
单项选择题What is the author trying to tell us（）
A．Happiness often goes hand in hand with pain. B．One must know how to attain happiness. C．It is important to make commitments. D．It is pain that leads to happiness.
