Table: british_gt_2009
Columns: round
circuit
date
pole_position
fastest_lap
winning_drivers
winning_team

Question: On how many different dates was the race at the Silverstone circuit?
SQL: SELECT COUNT("date") FROM british_gt_2009 WHERE "circuit" = 'Silverstone'

Question: When was the circuit Donington Park?
SQL: SELECT "date" FROM british_gt_2009 WHERE "circuit" = 'Donington Park'