"Are you listening to us?"
Translation:Dych chi'n gwrando arnon ni?
Because ar is the preposition used in combination with gwrando. As you learn more Welsh you will motice that certain prepositions are used with particular verbs to convey particular meanings - it is worth learning them together. For example:
- gwrando ar - to listen to
- edrych ar - to look at
- siarad â - to speak/talk to
- siarad am - to speak/talk about
- dianc rhag - to escape from
you can say 'gwrando arnynt' as well as 'gwrando arnon ni' can't you?