abrasion|abrasions

他摔倒后，手臂上有一处擦伤。

He had an ___abrasion on his arm after falling down.

孩子摔倒后，膝盖上有几处擦伤。

The child had several ___abrasions on his knees after falling down.

长时间穿这双鞋走路导致脚部皮肤因摩擦而磨损。

Walking in these shoes for a long time caused ___abrasion on the skin of my feet.