漏洞: leak, hole, gap, loophole...
公用: public, for public use...
传单: leaflet, flier, pamphlet...
功课: homework, assignment, task, classwork, lesson, study...
愚公移山: the old man moves mountains (idiom); where there's a will, there's a way...
出访: to go and visit in an official capacity or for investigation...
