When I use the verb 'быть' in the present, the predicate takes the nominative case, as in 'Я - высокий.' But when I change the tense, I sometimes feel I should use the instrumental instead (so 'Я был высокий' vs 'Я был высоким'). In what cases do I use each?


2 Answers 2


In short, your question seems to be a duplicate of the other one that had been previously asked.

Quotation from my answer to the previous one:

The difference is that быть + Instrumentalis is similar to a past perfective form (as a perfective action unrelated to a moment of utterance), while быть + Nominative would be compared to a present-perfective structure in a language where such a distinction exists.

As for the future tense, some decades or a century ago the phrase with Nominative compliment [будет журналист] might be equally correct, but nowadays it sounds as a little bit obsolete.

The usage of Instrumental as a copular compliment is similar to that of Essive (a case of an impermanent state) in Balto-Fennic languages and can be regarded as a Fenno-Ugric substrate.

  • Sorry about that, I'm new to the site and couldn't find the other question.
    – FM22
    May 14, 2017 at 13:52
  • @FM22 There is one more on the more or less the same topic (preicate/complement in Instrumental VS Nominative)
    – Manjusri
    May 14, 2017 at 16:02
  • If that's a Finno-Ugric substrate, then why instrumental is used with predicatives in Ukrainian and Polish? Were these languages also influenced by Finnic languages?
    – Yellow Sky
    May 16, 2017 at 17:53
  • Any examples? Anyway, see the Balto-Slavo-Germanic theory, where a common Proto-Slavic language is likely to be influenced by a (Proto)-Balto-Fennic language.
    – Manjusri
    May 16, 2017 at 17:57

Я был высоким is grammar correct option because we can ask я был (в прошлом) кем? - высоким человеком and instrumental case asking the same questions Кем? Чем? But the first option also can be used in speaking and writing, so it's not mistake just nuance. Also you can use short form like: Бунин был смел, честен в своих убеждениях. As you can see there is no ending at all смел (ый / ым)

  • so either is fine in speaking?
    – FM22
    May 14, 2017 at 12:25
  • it's sounds natural, be sure
    – sergentum
    May 14, 2017 at 13:14
  • Three variants are correct, nominative, instrumental and a short form.
    – V.V.
    May 16, 2017 at 7:28

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