Cyke,<br /><br />Just to supplement Mariek's helpful chart, here's a English sentence to put it into practice with a short explanation (using the most common uses of the cases) to help you with the books':<br /><br />O men, by your money, you give happiness to the girls of the poor country.<br /><br />-------------------<br /><br />Vocative is the case of direct address. In the sentence, who are we addressing? The men of course: "O men." Men is functioning as the vocative noun.<br /><br />Nominative is the case of the subject of a finite verb. Do we have a finite verb? Yes, we do. It's "give." What is its subject? "You" is. "You" in this case is a nominative pronoun.<br /><br />Accusative is the direct object. The direct object is what or whom the transitive verb is directly affects. We have a transitive verb here, don't we? It's "give." What is being given? Happiness is what's being given of course. Thus happiness is the accusative noun.<br /><br />Dative usually specifies the indirect object, to/for what or to/for whom something is done -- the thing that "benefits" from the verb. We know we are giving happiness, but to whom are we giving it? To the girls of course. "Girls" is the indirect object, and therefore, is the accusative noun.<br /><br />Ablative is commonly used after prepositions (not always) and usually to specify manner and means. We have a preposition here: "by." Also it is specifying the means. How are the men giving the girls happiness? By their money, they give the girls happiness. That's the means. "your money" is in the ablative.<br /><br />Genitive commonly indicates possession or some kind of origin, usually a relation expressed by "of." It mainly answers, "Whose?" So, do we have a "whose-of" relation? Yes, we do between "poor country" and "girls" Whose girls? The poor country's girls. "Poor country" is the possessor, and would be the genitive.<br /><br />I know the English sentence sounds like what one would hear in a Latin textbook, but I've been reading them a lot, so it came out that way. However, I hope my explanation clarified key ideas on grammatical cases.