大气中的臭氧层保护我们免受太阳有害射线的伤害。

The ___layer of ozone in the atmosphere protects us from the sun's harmful rays.

旧书上覆盖着一层厚厚的灰尘。

There was a thick ___layer of dust covering the old books.

为了修复这件家具，我们不得不铲掉好几层旧油漆。

To restore the furniture, we had to remove several old ___layers of paint.