1) It is five minutes past three
2)It is half past six o'clock
3)It is quarter past sixteen
4)It is ten past eiqhteen
5)I is seven twenty
6)It is twenty five past nine
7)It is ten to nine
8)It is five to nine
9)It is three o'clock o'clock
10)It is seven thirty-five
11)It is six forty five
12)It is twenty to four
Выражение o'clock используется только с круглыми цифрами(семь часов, восемь часов....)