What’s the hour between 11 o’clock and 1 o’clock?
A clock that strikes the hour strikes when it is exactly one o’clock, two o’clock, and so on. 整点
If something is between two things or is in between them, it has one of the things on one side of it and the other thing on the other side. 在…中间
About the hours
To avoid confusion, the correct way to express 12 o’clock is 12 noon or 12 midnight. Alternatively, the 24-hour clock system may be used – 12:00 and 24:00 (or 00:00) respectively.
The abbreviation a.m. stands for ante-meridiem (before the Sun has crossed the meridian line) and p.m. for post-meridiem (after the Sun has crossed the meridian line).