question, problem on homework etc. / a question; a matter (of time etc.) / a problem (something that needs to be dealt with); a trouble / an issue; a matter

the darkest place is under the candlestick; can't see the wood for the trees; people often known little of what happens under their noses; lit. "dark under a candlestick"

(informal) no problem

unthinkable, out of the question

practical question (problem)

matter of life or death / (idiomatic) an extremely urgent matter

viewing as a problem

to view as a problem

set of problems

problem; point at issue