Failure to detect error in verb and tenses

My teacher gave me an exercise recently, and I was instructed to look for errors in the sentences(verbs and tenses). However, there are some that I could not detect the errors.

1) I shall be grateful if you will let me have your notes.

Question: In the context of verbs and tenses, what is wrong with this sentence? I can't seem to find anything....unless you are saying "will" should not be there. but why?

2) The teacber emphasizes on the importance of passing the examination.

Question: Again, I could not detect any errors here. the tense and the verb seem ok to me.

3) I wish you were there to see the floats last night.

Question: Now, this one is a bit vague. Perhaps there is something wrong with the tense and the verb, but I am not particularly good at this sort of sentence.