I learned that 以 can also function to mean "a certain time" or "a fixed date", for example:
However, I also know that 于 can work in the same purpose, for example:
All the example sentences are from Pleco.
I feel that in these usages, 以 is used only to express "time", and not "place". So 生以上海 is wrong.
However, if it means "a fixed date", is there any difference (and if it is what is it) between 以 and 于?
Also, is there any such prepositions that function for the same purpose?