1 would have to be when jem was almost shot
I think it is accent marks and re-spelling because they always have accent marks when they are trying to help you pronounce the word and they help you recognize what letters to pronounce how to pronounce them.
Your answer will be I
Because Frankie is coming over to watch a movie with Sadie and me. Just doesn't work. However, Frankie is coming over to watch a movie with Sadie and I. Does work because you're talking about yourself and you're talking about another person.
So that's your answer.
I hope it helped! :)