напишите время 20.30,11.00,21.15,12.40,17.50,16.30

20:30 - It is half past eight p.m.

11:00 - It is eleven o\'clock.

21:15 - It is quarter past nine p.m.

12:40 - It is twenty to one.

17:50 - It is ten to six p.m.

16:30 - It is half past for p.m.

Или 

20:30 - It is eight thirty p.m.

21:15 - It is nine fifteen p.m.

12:40 - It is twelve forty.

17:50 - It is five fifty p.m.

16:30 - It is four thirty p.m.