(literary) they

conflict, trouble

to dispute

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

those (referring to things distant from the speaker)

(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