"She begs on her knees."
Translation:Ela pede de joelhos.
Yes, but you can also use "implorar" for "to beg" since it is more emphatic.
it pleases me to see that you and Paulenrique are still at it. Thank you for endless amounts of help over the years. I take it that the expression 'de' joelhos' replaces 'on his' and would that be the same for 'on his back' or 'on his butt'?
"On her knees" could be also translated as "ajoelhada", but it's marked as incorrect for me