This, too, evolved in response to industrial pollution. It developed black wings, so that it was invisible when it settled on soot-covered tree trunks.
在遭受工业污染后，他们进化为黑色翅膀，甚至当他们栖息在煤烟覆盖的树干时以至于能够达到隐形效果。
2
The inside of a chimney soon get covered in soot.
烟囱里面很快就会被煤烟覆盖。
3
Hundreds of buildings are covered in pale white soot.