_________ global temperatures rising, the UN Climate Change Conference was held in Cancun(坎昆), Mexico last year．

1. A.
   Prevented
2. B.
   Preventing
3. C.
   Having prevented
4. D.
   To prevent

________ 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

________ 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

________ 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

________ global temperatures rising, the UN Climate Change Conference was held in Cancun（坎昆）, Mexico last year．