英和和英

an elusive problem

a sticky question

a touchy subject

a nasty problem

a vexing problem

a trifling matter

an intractable problem

a stiff problem

an intricate problem

pose a problem

an involved problem

a baffling problem

a mystifying problem

a weighty problem

a ticklish question

a problem

a difficult problem

a difficult problem

a difficult problem

a worrying problem

a slight problem

a grave problem

an insoluble problem

a complicated problem

solve a problem

solve a problem

remedy a problem

an issue that becomes a problem

an unsettled issue

It is a hard question―a puzzling question―a perplexing problem―a stiff question.