How do we use "o'clock"?A student recently told me that he "went to bed at 11:30 o'clock".
This student made a simple mistake in spoken English. The rule is, "Only use o'clock when talking about the hour."
For example, "I get up at 6 o'clock every morning." But, "I get up at 6:15 (six fifteen) on Sunday mornings".
You can, for precision, add "am" or "pm" if it isn't clear. Someone who works at night might sleep until 3 o'clock, pm, and not 3 o'clock am. The twenty-four hour clock is not common in English, except in the military.
If you need to add minutes to the hour, do not use o'clock, instead just say the time and add the minutes.
For example, 4:30 can be said as: "four thirty" or "half past four". If it is in the morning, "four thirty in the morning" or "four thirty am". In the afternoon, "four thirty pm" or "half past four in the afternoon".
O'clock is a good expression to know, just be sure to use it correctly!