Find the extra word in each sentence

Ex2. Find the extra word in each sentence.
1. The boy who he sits next to me in class is called Vladimir.
=> The extra word: ........................
2. This book, which I started reading it last week, is really funny.
=> The extra word: ........................
3. Jean, whose her mother is a nurse, wants to be a doctor.
=> The extra word: .......................................
4. My mum and dad, who they got married fifteen years ago, met over thirty years ago.
=> The extra word: .......................................
5. The jeans which I was telling you about them are over there.
=> The extra word: .......................................