scratch his head

• vi. 迷惑不解(搔头皮)

scratch his head的用法和样例：

例句

1. Scratching his head, Tom thought of a good idea.
   汤姆搔搔头，想出一个好主意。
2. He was scratching his head over the question his teacher had asked him.
   对老师向他提的问题，他只能抓头皮，不知如何回答。