求翻译：国际能源机构的一项调查结果表明，美国、中国、俄罗斯和日本的二氧化碳排放量几乎占全球总量的一半。调查表明，美国二氧化碳排放量居世界首位是什么意思？

International Energy Agency, a survey showed that the United States, China, Russia and Japan, the world's carbon dioxide emissions accounted for almost half of the total. Survey showed that the United States ranks first in the world carbon dioxide emissions

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An International Energy Agency's investigation result indicated that, American, Chinese, Russian and Japan's carbon dioxide withdrawal accounts for the global total quantity nearly one half.The investigation indicated that, the American carbon dioxide withdrawal occupies the world first place

Results of a survey showed that the International Energy Agency, United States, China, Russia and Japan accounted for almost half the global total of carbon dioxide emissions. Surveys have shown that United States carbon dioxide emissions the highest in the world

Results of a survey showed that the International Energy Agency, United States, China, Russia and Japan accounted for almost half the global total of carbon dioxide emissions. Surveys have shown that United States carbon dioxide emissions the highest in the world