global temperatures rising, the UN Climate Change Conference was held in Cancun（坎昆）, Mexico last year．
A. Prevented
B. Preventing
C. Having prevented
D. To prevent
网友回答
A. Prevented
B. Preventing
C. Having prevented
(答案→)D. To prevent
解析：考查不定时做目的状语。 为了防止全球气温增长，去年联合国在墨西哥坎昆召开了气候大会。