Telling time on the hour

1. To ask what time it is in Russian we use the expression Сколько сейчас времени?
2. We answer with the word Сейчас, а number indicating the hour, and a form of the Russian word for o'clock.
3. There are three forms of the Russian word for o'clock: час, часа, часов.
4. We use the word час for 1 o'clock: Сейчас час.
5. We use the word часа for 2, 3, 4 o'clock: Сейчас 2, 3, 4 часа.
6. We use the word часов for 5 through 12 o'clock: Сейчас 5 - 12 часов.
7. To ask "At what time...?" we use the expression Во сколько...?
8. To answer, we use the preposition в followed by the time using the appropriate word for o'clock:
   В час.
   В 2, 3, 4 часа.
   В 5 - 12 часов.