user: Question: Which Surface has a Partner of Sorana Cîrstea?
Columns: ['Outcome', 'Date', 'Surface', 'Partner', 'Opponents', 'Score']
Types: ['text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['Runner-up', '17 August 2008', 'Hard', 'Sorana Cîrstea', 'Květa Peschke Lisa Raymond', '6–4, 5–7, [7–10]']
SQL:

assistant: SELECT "Surface" FROM "Table" WHERE "Partner" = 'Sorana Cîrstea';