Could native English speakers help me judge whether these relative clauses are correct or not? I'm working on my Master's thesis recently, which is a contrastive study and I need some help from native English speakers. After I made the following relative clauses, I became uncertain whether they are grammatically correct or not... So I'm really grateful if any native speakers here could take a look at them and judge their acceptibility based on a native's sense of English. I use this sign * to show a ungrammatical structure, which is conventional in linguistics... Brackets are used below to show something that can be omitted. Group A: 1. the man who you think (*that) told me this 2. the man whom you think (that) I saw 3. (1) the man to whom you think (that) I gave the book (2) the man whom you think (that) I gave the book to 4. (1) the man with whom you think (that) I traveled (2) the man whom you think (that) I traveled with 5. the man whose car you think (*that) was stolen 6. the man who you think (that) I am taller than Group B: 1. the man whose son told me this 2. the man whose son I saw 3. (1) the man whose son I gave the book to (2) the man to whose son I gave the book 4. (1) the man whose son I traveled with (2) the man with whose son I traveled 5. the man whose son's car was stolen 6. the man whose son I am taller than