It’s 21 past 8 (Alternative clock system).

20:21

It’s 21 past 8.

Correct answer

20:22

It’s 22 past 8.

Error: 1 minute later

20:05

It’s 5 past 8.

Error: read minutes starting from hour markings and adding minutes

16:40

It’s 20 to 5.

Error: confuse hour and minute hands