We move to our country house in/ during/ over the summer holidays.
The exhibition will be on/ over/ during the next three days.
Are all of the three OK & mean the same in the two cases?
I'd say that none of the country house options are wrong, but have different meanings in each case. For the exhibition options, we describe an exhibition as being "on". So we might say for example "The exhibition will be on during the next three days" or "The exhibition will be on over the next three days".
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I'd say that none of the country house options are wrong, but have different meanings in each case.
For the exhibition options, we describe an exhibition as being "on". So we might say for example "The exhibition will be on during the next three days" or "The exhibition will be on over the next three days".