user: Question: What transfer window has BRA as the country, with £3.4M as the transfer fee?
Columns: ['Name', 'Country', 'Type', 'Moving from', 'Transfer window', 'Ends', 'Transfer fee', 'Source']
Types: ['text', 'text', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['Song', 'CMR', 'Transferred', 'Bastia', 'Summer', 'Undisclosed', '£1M', 'BBC']
SQL:

assistant: SELECT "Transfer window" FROM "Table" WHERE "Country" = 'BRA' AND "Transfer fee" = '£3.4M';