紧扣

紧扣	jǐn kòu	to stick closely to (a topic or theme etc)
紧	jǐn	tight / strict / close at hand / near / urgent / tense / hard up / short of money / to tighten
扣	kòu	to fasten / to button / button / buckle / knot / to arrest / to confiscate / to deduct (money) / discount / to knock / to smash, spike or dunk (a ball) / to cover (with a bowl etc) / (fig.) to tag a label on sb / (Tw) (loanword) code
扣	kòu	button