It is ten o’clock = it is 10 a.m.
It is eleven o’clock = it is 11 a.m.
It is twelve o’clock = it is 12 p.m.
It is seven o’clock = it is 7 p.m.
It is a quarter past seven.= it is 7:15 p.m.
It is nine o’clock = it is 9 p.m.
It is half past nine= it is 9:30 p.m.
It is ten o’clock = it is 10 p.m.