CASES

There are five cases in Romanian: nominative, accusative, genitive, dative, and vocative.

The nominative case is the usual form of some parts of the speech such as nouns, adjectives, pronouns and less frequently numerals and participles, and sometimes does not indicate any special relationship with other parts of speech.The nominative case marks the subject of a verb, as opposed to its object or other verb arguments.Basically, it is a noun that is doing something, usually joined with the accusative case.

The accusative case is used to mark the direct object of a transitive verb. The same case is used to indicate duration of time,to indicate direction towards which,in indirect statements.Basically, it is a noun that is having something done to it, usually joined with the Nominative case.

Example:

I see the flower. - Eu văd floarea-> the flower(floarea) is is the direct object of the verb "see".

The genitive case or possessive case is the case that marks a noun as being the possessor of another noun.
In usual genitival phrases such as "casa omului"(the house of the man), the genitive is only recognized by the specific ending ("-lui" in this example) and no other words are necessary. However, in other situations the genitival article is required, as for example "în câteva camere ale casei" ("in some of the house's rooms').

The dative case is used to indicate the noun to whom something is given. In romanian dative phrases the noun in the dative is doubled by a pronoun.The position of this pronoun in the sentence depends on the mood and tense of the verb.

Example:
I give a book to [my] friends.-Le dau o carte prientenilor.

The pronoun "le" doubles the noun "prietenilor" without bringing any additional information.

The vocative is less used as it is normally restricted to nouns designating people or other things we can address.

Example:
And you,Maria?-(Şi) tu,Maria? -The noun "Maria" is in vocativ case.