Question: What year did Freddie Frith win the 350cc and Enrico Lorenzetti win the 500cc?
SQL: SELECT "Year" FROM "2-16661710-4" WHERE "350 cc" = 'Freddie Frith' AND "500 cc" = 'Enrico Lorenzetti';

Question: What track was used in 1926?
SQL: SELECT "Track" FROM "2-16661710-4" WHERE "Year" = '1926';

Question: Who won the 250cc in 1927?
SQL: SELECT "250 cc" FROM "2-16661710-4" WHERE "Year" = '1927';

Question: What grand prix was held at Granollers?
SQL: SELECT "Designated Grand Prix" FROM "2-16661710-4" WHERE "Track" = 'Granollers';

Question: Who won the 350cc at Sachsenring?
SQL: SELECT "350 cc" FROM "2-16661710-4" WHERE "Track" = 'Sachsenring';