だれが一番優れているか、この際はっきり決めましょう。

who

indicates sentence subject (occasionally object); indicates possessive (esp. in literary expressions); but; however; still; and

number one; first; first place; best; most; game; round; bout; as a test; as an experiment; by way of experiment; by way of trial; tentatively; song (e.g. in Noh); piece

to surpass; to outstrip; to excel

indicates a question (sometimes rhetorical); or; whether or not; some- (e.g. something, someone); indicates doubt, uncertainty, etc.; emphatic prefix; suffix forming adjectives or adverbs; in that way

this (something or someone close to the speaker (including the speaker), or ideas expressed by the speaker)

on the occasion of; circumstances; juncture

clearly; plainly; distinctly; to be clear; to be definite; to be certain; to be exact; to become clear; to clear up

to decide; to choose; to determine; to make up one's mind; to resolve; to set one's heart on; to settle; to arrange; to set; to appoint; to fix; to clinch (a victory); to decide (the outcome of a match); to persist in doing; to go through with; to always do; to have made a habit of; to take for granted; to assume; to dress up; to dress to kill; to dress to the nines; to carry out successfully (a move in sports, a pose in dance, etc.); to succeed in doing; to immobilize with a double-arm lock (in sumo, judo, etc.); to eat or drink something; to take illegal drugs