1. Chinese tradition dictates that children kowtow before parents before the children receive a red envelope from the parents on Lunar Chinese New Year's Eve.2. In ancient times a wife would kneel down before her husband and bow with her face to the ground to show respect.
 kowtow bow with one's face to the groundbow with one's face to the ground 很貼切的形容磕頭的動作。
She is shy, but when there is a guest at home, she becomes excited and hyperative and out of control.