The Russian language uses six cases (nominative, genitive, dative,
accusative, instrumental, and locative), with an occasional seventh case,
the vocative. In addition, three genders are used (masculine, feminine, and
neuter). Russian verbs use three tenses (past, present, and future).
Consequently, Russian grammar is complex to learn.
For novice speakers of Russian, the important thing to keep in mind
is that word suffixes will changed depending on the context of the sentence.