Fill in the blanks with suitable Prepositions :-(1) The village was destroyed ....... fire. (2) I have not seen him ........ Wednesday last. (3) I...

The most likely answers here are

1. by


2. since


3. on or perhaps at -- on is more American, but it seems to me that I have heard British people use "at."


4. on my


5. against

Remember that a preposition typically talks about how one thing (the object of the preposition) is related to the rest of the sentence.  So prepositions are things like "on" and "beside" that show relationships between two things.  If you can remember that, you can have a better chance of figuring out prepositions for yourself.

I was once told that you could learn prepositions by filling in the sentence "The rabbit is ________ the box.  And anything that you could put in that space is a preposition.  It's not quite true, because you could put "chewing" there.  But any other word (s) like "in" or "by" or "on" or "next to" is a preposition.