someone's back is turned

US /ˈsʌm.wʌnz bæk ɪz tɜrnd/
UK /ˈsʌm.wʌnz bæk ɪz tɜrnd/
"someone's back is turned" picture
1.

cuando alguien está de espaldas, cuando alguien no está prestando atención

when someone is not looking or paying attention

:
The children started playing pranks as soon as their mother's back was turned.
Los niños empezaron a hacer travesuras tan pronto como su madre se dio la vuelta.
He always tries to sneak a cookie when my back is turned.
Siempre intenta robar una galleta cuando le doy la espalda.