I am a native french speaking person so I don't need to think about it but I guess that the difference is just grammatical : - QUI is the subject in the relative Je lis un livre QUI me tombe des mains = Je lis un livre, CE LIVRE me tombe des mains. - QUE is the object in the relative Je lis un livre QUE je n'aime pas = Je lis un livre, je n'aime pas CE LIVRE Qui and que are different words in french but they probably come from the same word in Latin but in different cases (nominatif and accusatif in french). Je and me (or I and me in English) are another example of the remaining of Latin cases in french (and even in English). I know that my english is a bit ... freestyle but I hope that this will help you anyway.

Hi Mark Here are the correct sentences: Je lis un livre qui est ennuyeux "Qui" in those sentences is the relative pronoun mainly used in defining/non defining clauses, so it stands for: I read a book which is boring, which is a defining clause here If you say: "My book, which is very long, is boring" this is a non defining clause and the clause "which is very long" just adds extra information about the book. "Which" is the same meaning in this clause as well, it means "qui" Je mange des frites qui sont froides Relative pronoun/defining clause: the fries which are cold Je bois un coca qui est chaud Relative pronoun/defining clause again: the coke which is hot The last one is correct! Does that make sense?