Can I ask a favour of you?

能请你帮个忙吗？

《牛津词典》

May I ask a favour of you?

能不能请你帮个忙？

《新英汉大辞典》

She rang up to ask a favour of me.

她打电话请我帮个忙。

youdao

Councillors have voted in favour of Cornwall homeowners being forced to ask permission to use their property as a second home or holiday let.

BBC: Councillors vote in favour of second home planning permit

He added that if Mr Osborne had decided that the UK should contribute "a fraction more" he would have had to ask for parliamentary approval, predicting that the government would have had difficulty persuading MPs to vote in favour of such a move.

BBC: Osborne faces IMF funding backlash from MPs