one of the difference is distance from the speaker, physical or emotional. like "this" and "that" in English. "ano" is farther than "sono". speaker <--> kono hito <--> sono hito <--> ano hito it is "ko so a do kotoba" in japanease.("dono hito"=who or whom add to above) "kore" "sore" "are" "dore" "kono toki" "sono toki" "ano toki" "dono toki(rare "itsu" is better)" "kore kara" "sore kara" "are kara" "dore kara"