Which preposition would be correct?
It was the happiest day of / in my life.
quote:and this is what I'd use in a test
quote:The first emphasizes belonging to the sequence of days making up his/her life, the second shows that very day inserted/embedded in that sequence.
quote:Why don't you read the continuation to the message?
Also, I assume the OP question was raised before a test, and I will provide whatever I think best supports my argument. The student will hopefully memorize the advice and use it if she wishes at the time of the test.
Not to speak of the fact that by following my search links the students can see patterns used by some of the best writers , much better than they could get from someone else?