Catalytic converters on the cars and better filters on power-plant smoke-stacks have greatly reduced smog, smoke and soot in the air.
汽车的催化裂化器以及发电厂的过滤器降低了空气中的烟、雾、尘。
2
Most recognizable of the ship designs are the ship's smokestacks, but the fourth stack was actually just artistic in nature and served no functional purpose.
烟囱是船舶最容易辨认的设计，但其实，第四个烟囱只有装饰美化作用，并没有任何的实际功能。
3
Smokestacks are seen at a coal power plant in West Virginia.