Как на будет 1 час,1-30,12-00,20th,10-45,5-15,и 12st

1 час - It's one o'clock
1-30 - It's half past one
12-00 It's twelve o'clock
20th twentieth
10-45 - quarter to eleven
5-15 quarter past five
12st - может 21st? - twenty first?
12th - twelfth