Replace your trainers when they start to show signs of wear.

【wear】运动鞋开始出现磨损迹象就要更换。

And, in the months after the surrender, the deep soft nap began to show signs of wear and finally the heavy warp and woof showed through in spots where heels had worn it and spurs dug carelessly.

而且，几个月来，地毯上的绒毛已开始出现磨损的迹象，尤其是鞋跟践踏和靴刺不小心划着的地方，连那下面的线纹也快露出来了。