[T, I] to rub your skin with your nails, usually because it is itching 挠，搔（痒处）
~ sth/yourself
John yawned and scratched his chin.
约翰打个哈欠，挠挠下巴。
The dog scratched itself behind the ear.
狗用爪子挠挠耳后。
~ (at sth)
Try not to scratch.
尽量别挠。
She scratched at the insect bites on her arm.
她挠了挠胳膊上虫咬的包。