So, when I write or speak a sentence with interrogative pronouns I need to put the interrogative pronoun in the same case it refers. For example, What fruit do you like? in Russian will be который фрукт ты любишь?, фрукт doesn´t change because is an inanimate noun of masculine gender and, in the sentence, is in accusative case. который that refers to фрукт doesn´t change because фрукт is an inanimate noun and according to the rules there´s no need to change it. который is in accusative case too. Is it that?