It’s a quarter past 9.

21:15

It’s a quarter past 9.

Error: read digital clock as if it were an analogue clock

21:15

It’s a quarter past 9.

Error: read quarter as a number

20:45

It’s a quarter to 9.

Error: confuse ‘past’ and ‘to’

20:45

It’s a quarter to 9.

Error: confuse ‘past’ and ‘to’ and read quarter as number