40-45 40-50 45-50 50-55 50-60 55-60 adult americas argentinean brazilian central america chalkboard class color colour educator fellow fifties fifty forties forty gentleman guy human human being indoor inside instructing instruction intelligence lecturer male mexican mid life middle age middle aged middle-age middle-aged one person schoolroom south america south american speech studying talking teaching three-quarter length toiling tuition tutoring western european wisdom work blackboards caucasians classrooms colleges colored colors educate educates educated educating hold holds held knowledgeable latins learn learns learned learnt lecture lectures lectured men man's men's maturity occupations photographic schools stood teachers vertically verticals work works worked writings write writes written wrote chalkboards colours coloured educators holds lectures males mexicans middle aged persons speeches study studies studied talk talks talked toil toils toiled