This is a tough nut to crack.

这是一件棘手的事。

youdao

It is a tough nut for him to crack.

这对他而言是一个难题。

youdao

Sunday's match will be a tough nut to crack.

周日的比赛将是场硬仗。

youdao

All the same, Florida looks a tough nut to crack for any Democrat.

ECONOMIST: Two big ’gators pounding away | The

On an afternoon when Fulham's well-organised defence proved a tough nut to crack, Carroll's improved mobility and goal threat were plain to see.

BBC: Chris Hughton talks up Andy Carroll's England claims

Solwhit proved a tough nut to crack at the head of affairs and looked as though he would take the glory again before Hurricane Fly's late burst.

BBC: Hurricane Fly triumphs in Punchestown Champion Hurdle