Hello Sky.stars, "Nada lost her book". or "Nada's book is lost" ( the passive form) You simply substitute "can not find" by "lose" Here "lose" means to lose sight of her possession ( the book in this case). The book is somewhere there but she can not find it. It is not adequately proper to use this form here: " Nada can not find her lost book". It is an unnecessary repetition, because what she can not find is by definition "lost".

Question: 'Nada cannot find her book.' How can I use 'lost' in this sentence? Answer: 'Nada cannot find her LOST book.' It is an adjective here which means 'that cannot be found'. You can also use it as a verb (the past simple of 'lose'): 'NadaLOST her book.' Or: 'Nada HAS LOST her book.' (present perfect) This means that she doesn't have the book now. She can't find it.