silver stain

例句：

1. 1. The old painting had asilver stain on the back.
   这幅旧画背面有一道银斑。
2. 2. Thedress has a silver stainon the sleeve.
   这件裙子袖子上有一道银斑。
3. 3. Thesilver stain on the tableis from the spilled coffee.
   桌子上的银斑是咖啡洒出来的。