help me how to give hint in quiz

hi am making quizbot. i need source code to give hint(show 2 3 word in from answer in there pattern) as the time reach the hint(hint of give word will increase).
ex: who is first man who walked in moon.
at first time interval i.e: 1 to 10 seconds it display in hint: N*** A********
at second time interval i.e 10 to 20 seconds it display in hint: N**l A*******g
at third time interval i.e 20 to 30 seconds it display in hind: Ne*l Ar******g


something like that.. help me thanks in advance