If we some measures we might have prevented the environmental pollution.A. takeB. had tak

问题补充：

If we some measures, we might have prevented the environmental pollution.

A. take

B. had taken

C. took

D. have taken

答案：

A. take

(答案→)B. had taken

C. took

D. have taken

解析：考查时态。句意：我们已经采取了措施，我们应该能阻止环境污染。条件从句中是对过去已完成动作的假设，故用过去完成时态，选B。