12:20 — It is twenty past twelve p.m.
14:15 — It is quarter past two p.m. — It is fifteen past fourteen.
10:20 — It is twenty past ten a.m.
11:10 — It is ten past eleven a.m.
9:50 — It is ten to ten a.m. — It is fifty past nine.
20:30 — It is half past eight p.m. — It is thirty past twenty.