SELECT "Score" FROM table_12335 WHERE "Surface" = 'clay' AND "Date" = 'april 7, 2008'
What was the April 7, 2008 score on a clay surface?
CREATE TABLE table_12335 (
    "Date" text,
    "Tournament" text,
    "Surface" text,
    "Opponent in the final" text,
    "Score" text
)