問題詳情

140. Studies showed that the accumulation of carbon dioxide ______ average global temperatures to rise nearly four degrees Fahrenheit by the twenty–first century.
(A) have caused
(B) has caused
(C) have been causing
(D) causing

參考答案

答案:B
難度:適中0.44898
統計:A(11),B(22),C(13),D(2),E(0)

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