I was given this sentence

Сегодня мы с Джулией собираемся в поездку в Россию по программе обмена студентами.

по программе — dative, обмена — genitive, студентами — instrumental

why are these all in different cases? i understand that after it is required to be in the dative case but i dont know why exchange changed to genitive and students changed to instrumental.

the way i thought it worked was that everything referring to the initial thing you are talking about will be changed in the same case, so program is in dative , so i thought everything would be dative.

Is there a general rule i can follow to understand when to change a word into a specific case? i am really confused on how that works, especially in this sentence

i would love as much information and as many tips as you can offer to help me with this

thank you in advance

2 Answers 2


It's because every next word is governed by its predecessor

  1. The preposition по in this sentence governs Dative, that's why программа is in Dative

  2. Обмен is in Genitive because it answers the question программа чего? that is of what? - of exchange

  3. Студенты is in Instrumental because the verb обмениваться, of which обмен is a gerund, governs Instrumental case - обмениваться кем/чем? and by extension обмен кем/чем?

Putting студенты in Genitive would misrepresent the intended meaning of the phrase because обмен студентов in Russian may mean either exchange done by students and NOT exchange with students or exchange of students for someone/something else, other than their peers.

Genitive of the following noun doesn't convey the meaning of reciprocal exchange of students because it makes the noun обмен a gerund of the verb обменивать rather than обмениваться. Обменивать in its turn doesn't govern Instrumental case.

So basically there're обмен кем/чем? and обмен кого/чего? and they mean different things.

The only rule is to follow cases that convey the meaning relevant to a phrase or a sentence, which of course needs to be studied, learned and memorized.


С Джулией - instrumental. В Россию, в поездку - accusative.

The words you mentioned are not homogeneous members of the sentence. Try to say it in English and you will see how differently the relations between the words will be expressed.

If you need a table of the cases usage in Russian, you are welcome.


But it is not how you can learn doing it correctly. The cases are studied one by one, very gradually, for different types of declension, for different cases of usage.

  • i understood why julia was in instrumetnal and i understood why those two were accusative, those were obvious ones, after C it is always in instrumental, and after B it is always prepositional, i don't get the last part of the sentence because there is no visible reason as to why they are in these cases
    – Almonds812
    Aug 17, 2019 at 20:33

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