Questions & Answers about Ночью я видел ужасный сон и проснулся очень рано.
Why is it ночью and not в ночь or в ночи?
Ночью here is the instrumental case of ночь, used adverbially to mean “at night”.
Russian often uses the instrumental (without a preposition) to express time in a general sense, like:
- днём – in the daytime
- утром – in the morning
- вечером – in the evening
- ночью – at night
You can say в ночь or в ночи, but they are more specific/poetic and usually need extra context (e.g. в ту ночь – on that night). Ночью is the most natural everyday way to say “at night” in this kind of sentence.
Why is ужасный сон in this form? Which case is сон in?
Ужасный сон is in the accusative case because it is the direct object of the verb видел.
- Nominative: ужасный сон – a terrible dream (subject)
- Accusative: видел ужасный сон – (I) saw a terrible dream (object)
For inanimate masculine nouns like сон, nominative and accusative look the same, so the form doesn’t change.
Why is it видел and not увидел? Aren’t both “saw”?