Definition: to rub your skin with your nails, often to stop it itching Level: B2
我的皮肤太痒了，我忍不住不停地挠。
My skin was so itchy that I couldn't stop ___scratching.
他在挠蚊子咬的包。
He was ___scratching at his mosquito bites.
她一边思考问题，一边若有所思地挠着头。
She ___scratched her head thoughtfully as she considered the problem.
