Table: t_1981_vfl_match_3
Columns: home_team
home_team_score
away_team
away_team_score
venue
crowd
date

Question: What day did Collingwood play as the home team?
SQL: SELECT "date" FROM t_1981_vfl_match_3 WHERE "home_team" = 'collingwood'

Question: Who was the away team at Princes Park?
SQL: SELECT "away_team" FROM t_1981_vfl_match_3 WHERE "venue" = 'princes park'

Question: Who was Hawthorn's away opponent?
SQL: SELECT "away_team" FROM t_1981_vfl_match_3 WHERE "home_team" = 'hawthorn'