Which is the more correct interpretation of Он до полночи думал над проблемой:

1) He was thinking about the problem until midnight.

2) He was thinking about the problem for half the night.

My guess is 1, because до is followed by the genitive case, and the genitive of полночь (midnight), is полночи.

But there is also the word полночи (half a night), so maybe 2 is correct.

5 Answers 5


Words Полночь and its counterpart Полуночь are very special. In Nominative and Accusative cases we normally say Полночь, yet in other cases forms of Полуночь (including до полуночи = until midnight) are used much more frequently.

Having said this, Genitive case "до полночи" is still considered legal and means "until midnight". So this sentence exactly means (1) "He thought about the problem until midnight".

On the other hand, (2), i.e. "до полночи" = "about half a night", is also formally possible. Yet the latter looks too ugly and should be ruled out. Anyone, trying to say "about half a night", would choose "почти полночи" over "до полночи".


I think this is a wrong sentence. Formally it should be 2) but the context suggests the author meant 1). The author should use "до полуночи".

As Alex S. pointed out in the comments, it would be OK and have the 2) meaning if one more word is inserted. These both variants are correct:

Он, бывало, до полночи думал над проблемой (meaning 2)

Он до полуночи думал над проблемой (meaning 1)

  • I suppose the origin of the mistake is phrase "ночь-полночь". Probably the author was about to write "сидел ночь-полночь, думал...", but eventually realized it's a colloquial form and made a correction. Was not very accurate while correcting though. Mar 22, 2016 at 11:38
  • In case of 2) the sentence must be without до.
    – Abakan
    Mar 22, 2016 at 17:10
  • @Alex.S Когда мы играли в "Мафию", одна игра могла у нас занять до полночи. Когда он готовился к экзаменам, одна задача могла у него занять до полночи. Ударение в полночи на последний слог, то есть это половина ночи (по длительности), а не момент времени.
    – Anixx
    Mar 22, 2016 at 18:36
  • Примеры не аналогичны предложению из вопроса – в них есть неоднократность действия. Если же предложение из вопроса слегка расширить – например, "он, бывало, до полночи думал над проблемой" – то возможен и второй вариант.
    – Abakan
    Mar 23, 2016 at 8:07
  • @Alex.S поэтому я и говорю, что из контекста видно, что автор имел в виду другое.
    – Anixx
    Mar 23, 2016 at 12:11

I guess that the intended meaning is "until midnight", but the correct form is "до полуночи", not "до полночи". For (2), the correct sentence would be "Он полночи думал над проблемой", without the preposition "до".


Although до полуночи (meaning till midnight) is more frequent, до полночи is also correct and has the very same meaning.


Он до полУночи думал над проблемой - means exactly the same as 1. Its just a grammatic mistake in ur word, because otherwise it makes no sense. You can trust me, I am native russian.

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