君はそれらの難題に対処しなくてはならない。

tbd

You have to cope with those difficult problems.

一難去ってまた一難、またまた難題が社長からトップダウンで降りてきたよ。

tbd

No sooner had we finished working on one tough problem than the president sent us yet another straight from the top.

それは難題だ。

tbd

That's a tall order.