The air is polluted with a lot of black smoke by factories that burn coal.
建议把句子中的by前面加过去分词produced,这样produced by factories that burn coal 就作为后置定语,修饰 a lot of black smoke。这就避免了with短语和by短语都去修饰is polluted。
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第1个回答 2020-04-01
with...smoke放最后面。