I came across this from a speech transcript:
When we were on the boat, we were hoping to see some dolphins. We were unlucky on the two days we went, but we did get to see some eagles flying close to land.
If here "the two days" is seen as a longer period of time than a particular day, shouldn't "in/over/during/etc" have been used?
Or is "the two days" two particular days in the speaker's mind? In that sense, has the defining clause "we went" got something to do with it?