531.Over the past decades,sea ice ______ in the Arctic as a result of global warming.
A.had decreased
B.had been decreased
C.has decreased
D.has been decreased
532.Look!How long ______ like this?
Three weeks!It's usual here that rain _______ without stopping these days of the year.
A.has it rained;pours
B.has it been raining;pours
C.is it raining;is pouring
D.does it rain;pours
531.答案是C;此题冰减少，decrease应考虑用主动语态。
532.答案是B;how long与完成时连用，但此处根据下文without stopping暗示，第一空用完成时更妥；第二空陈述事实，用一般现在时。
