million of pounds'worth of damage ______ by a storm which swept across the north of English last

问题描述:

million of pounds'worth of damage ______ by a storm which swept across the north of English last
night. a,has been causedb,had been causedc,will causedd,will have been caused老师说选a为什么不选b?

句子强调的是“从last night到现在”的结果,所以用“has been caused".
如果用B,强调的是last night以前的事情,不符合句子的语境.
求个好评~