To shake one's head means to move one's head from side to side, typically as a gesture of negation, disbelief, or disagreement. It is a common body language gesture used in many cultures around the world. Here are some examples of how to use it in a sentence:

"I asked her if she wanted to go to the movies, but she shook her head." (她摇头表示不想去看电影。)

"The teacher shook her head in disapproval when she saw the student's messy notebook." (老师看到学生那乱七八糟的笔记本，摇了摇头表示不满。)

"He shook his head in confusion when he heard the news." (当他听到这个消息时，摇了摇头表示困惑。)

The origin of this gesture is not clear, but it is likely that it has been used by humans for a long time as a way to communicate non-verbally. It is possible that it evolved as a way for people to show their emotions or intentions without using words.