The second source of carbon dioxide lies outside Europe.

第二个二氧化碳的来源在欧洲之外。

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There could also be good news for transport, the next biggest source of carbon emissions.

对于运输—二氧化碳排放的第二大来源，也是好消息。

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A second source of carbon monoxide is Alberta, Canada, where large wildfires are burning.

另一个一氧化碳污染源在加拿大阿尔伯塔省，那儿正燃烧着熊熊大火。

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There could also be good news for transport, the next biggest source of carbon emissions.

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