It might have been at Christmas that Jonh gave Mary handbag.
这是强调结构吗?还是定语从句?状语从句?
情态动词可以用于分裂句中(强调句),在强调的前提下让be 具有情态意义,这样可以强化或弱化be 的意义,甚至否定它。例如:
It might have been John that bought a new book for Mary yesterday.(弱化)
It may be next week that she leaves for Tokyo.(弱化)
It mast have been a thief that broke in the house.(强化)
It can’t be Tom that has damaged the desk.(否定)
It will not be you that will have to take the blame for this.(否定)
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