Let me try to explain to the best of my ability. What is an Attributive Clause? an attributive clause is an entire clause that adds more information about a noun; in other words, the clause serves as a modifier of that noun. An attributive clause can either be restrictive or nonrestrictive. Restrictive attributive clauses serve to specify precisely which noun is being referred to. For restrictive attributive clauses, the relative pronoun “that” is used, never “which” (at least in American English); when the antecedent noun is a person, the relative pronoun “who” is used. Here are examples of attributive clauses: (1) Restrictive attributive clause: “She liked the laptop that she saw in the computer shop last night.” Here, “that she saw in the computer shop last night” is the restrictive attributive clause and it modifies the noun “laptop.” (2) Restrictive attributive clause (for a person as antecedent noun): “The writing contest winner was the young girl who wrote about a thin, beardless Santa Claus.” Here, “who wrote about a thin, beardless Santa Claus” is the restrictive attributive clause and it modifies the noun “girl.”

He has written a book whose name I have forgotten. Only people can be described by who, whose, or whom while things are described by which, what, and that He has written a book the name of which I have forgotten. You would need to add a comma before “the name” because it’s an appositive phrase. Otherwise this one is technically correct, but putting “of” in front of “which” is so “grammatically correct” that we associate it with old books and stuffy formal writing. He has written a book that I have forgotten the name of. This would be a good popular form. Although it’s weird to put of and the end of the sentence for on-native English speakers, you kind of just have to think about the rebel nature of American pop culture and speech, and kind of switch the order up and make some mistakes in your english on purpose. Just look up which ones everybody makes beforehand. (: He has written a book of which I have forgotten the name. This one is also correct, but it’s again in that formal tone (equivalent to the “name of which” one. Keep up the good work! And just remember, when it comes to English, the rules barely make sense even to the kids in American schools, so straight memorization is key to most English grammar.

Great job, you've mastered this subject. I see what's bothering you let me try to explain: There are often prepositions in attributive clauses, and a relative pronoun is the object of that preposition. In everyday English, the preposition is usually placed at the end of the relative clause and the pronoun may be included or omitted. Here are some examples: Daniel has described how he does it in a book "in which" he writes about his life. One skill "for which" all savants are known for is an extraordinary memory. Is that the man "with whom" she arrived? We passed a giant toadstool in the forest, "under which" fairies were sitting. In more formal English, usually in written English we tend to put the preposition before the relative clause: It was the river "in which" the children preferred to swim. The person "with whom" he is negotiating is the Chairman of a large company. In less formal, usually spoken English prepositions at the end of relative clauses are common: The music "which" Julie listens "to" is good. My brother met a woman "who" I used to work "with". Hope this helps ^-^

Nonrestrictive attributive clauses provide more information about the antecedent noun, but it’s presumed that the specific noun being referred to is already known by the reader either by context or logic. For nonrestrictive attributive clauses, the relative pronoun “which” (never “that”) preceded by a comma is used; when the antecedent noun is a person, the relative pronoun “who” is used. A non-restrictive attributive clause is optional to the sentence; the sentence will remain grammatically and structurally sound without it. Here are examples of nonrestrictive attributive clauses: (1) Nonrestrictive attributive clause: “Many people from the provinces flock to Manila, which is the capital of the Philippines.” Here, “which is the capital of the Philippines” is the non-restrictive attributive clause, modifying the antecedent noun “Manila.” (2) Nonrestrictive attributive clause (for a person as antecedent noun): “Let us all congratulate Mr. Roberto Cruz, who as we all know has topped the medical licensure exam.” Here, “who as we all know has topped the medical licensure exam” is the non-restrictive attributive clause, modifying the antecedent noun “Mr. Roberto Cruz.” Hope this helps ^-^