the aforementioned (person)

think / meditate / consider / expect / reflect / prepare / make up one's mind / imagine / contrive

deep, profound

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

deep, close, thick, profound

deep, profound

(informal) no problem

unthinkable, out of the question

practical question (problem)

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