问题
选择题
In the past decades, 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
答案：B
考查时态。In the past decades通常都与现在完成时连用或者现在完成进行时连用。句意：在过去的几十年里，由于全球变暖，北极海冰一直在融化。