my grammar book says that in case of identifying clauses it is possible to use both "which" and "that". (e.g. The book that/which I gave to you is really easy to read). Are there any cases where "that" is the only possibility and "which" is not correct?
Thank you very much.
In BrE, either can be used for restrictive clauses. In AmE, "that" is far more commonly used for restrictive clauses.
restrictive clause: The book that I gave you is easy to read.
nonrestrictive clause: This book, which was written by James Joyce, is difficult to read.
Pope of the Dictionary.com Forum