题目内容
Carbon dioxide ________ from burning fuels is the most common of the so?called greenhouse gases.
A.producing
B.having been produced
C.to be produced
D.produced
D
考查非谓语动词。由句意知空中填一个非谓语动词做后置定语,与其前的carbon dioxide为动宾关系,故选produced表被动。

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