I am new here.
This confusion has been stuck inside my mind for like forever.
I am sorry if a similar question to this has been raised and answered here before.

"IT IS YOU WHO IS/ARE THE CHEATER"
Please can anyone tell me what is the correct usage of this sentence quoted.

Pardon me if I have used wrong English in this thread. If there is any defect in my writing please point out too.

Ahh.... Also want to know whether the usage of prepositions in the following typed sentences are correct.
1.WRITE IT IN THE BOOK.
2.THE GRAPH IN THE BOOK.

Thank you so much.