In the past few years sea ice in the Arctic as a result of global warming.A. had meltedB

问题补充：

In the past few years, sea ice in the Arctic as a result of global warming.

A. had melted

B. has been melting

C. melted

D. is melting

答案：

A. had melted

(答案→)B. has been melting

C. melted

D. is melting

解析：考查时态。根据in the past few years可知是与完成时连用的，在根据句意是指海冰一直都在融化。所以使用现在完成进行时。句意：在过去几年里，因为全球变暖，海冰一直在融化。