In case you were wondering

When you need to find out the time, ask: Кото́рый (сейча́с) час?

You'll hear in reply:

Сейча́с час.It's one o'clock.
Сейча́с два часа́.It's two o'clock.
Сейча́с де́сять часо́в.It's ten o'clock.

When you need to know WHEN? you may use one of the following two

questions: Когда́? and В кото́ром часу́?

There are two ways of answering these questions:

  1. Когда́? This is less specific and may be answered by saying:

    У́тром.In the morning (from about 5:00 am to noon)
    Днём.In the daytime (from noon to about 6:00 pm)
    Ве́чером.In the evening (from 6:00 pm to midnight)
    Но́чью.At night (from midnight to about 5:00 am)
  2. В кото́ром часу́? This is more specific and indicates the hour:

    В час.At one o'clock.
    В два/три/четы́ре (часа́).At two/three/four o'clock.
    В пять/шесть/семь (часо́в)At five/six/seven o'clock.

    В во́семь /де́вять /де́сять (часо́в)

    В оди́ннадцать /двена́дцать (часо́в)

    At eight /nine /ten

    At eleven /twelve o'clock.

To indicate am add но́чи or у́тра after the hour:

For p_m, add дня or ве́чера.

В час.At 1:00 am.
В четы́ре три́дцать.At 4:30 am.
В де́вять со́рок пять.At 9:45 am.
В трина́дцать де́сять.At 1:10 pm. (13:10)
В семна́дцать три́дцать.At 5:30 pm. (17:30)
В два́дцать пятна́дцать.At 8:15 pm. (20:15)
В два́дцать три три́дцать.At 11:30 pm. (23:30)

But you will also hear these:

В полови́не пя́того утра́.At 4:30am. (lit. half five in the morning)
Без пятна́дцати де́сять утра́.At 9:45am. (lit. 10 less 15 [minutes])
В де́сять мину́т второ́го.At 1:10pm. (lit. 10 minutes of the second hour)
В полови́не шесто́го ве́чера.At 5:30pm. (lit. half six in the evening)

Russian uses the Genitive case and the unchanging negative verb forms НЕТ (present tense) HÉ БЫЛО (past tense) and HE БУ́ДЕТ (future tense) to show that someone or something is lacking/missing.

Compare the following sentences:

Russian uses special forms of the numerals with the words:

and a few others which exist only in the plural.

одни́ су́тки(but: оди́н ребёнок, оди́н сын, одна́ дочь)
дво́е су́токдво́е дете́й
тро́е су́токтро́е дете́й
че́тверо су́токче́тверо дете́й
пя́теро су́токпя́теро дете́й

Note that these numerals are ALWAYS followed by the noun in the GENITIVE PLURAL CASE.

Study the following examples: