Score F–A of 3–0, and a Date of 31 july 2007 had what opponents?
CREATE TABLE "pre_season_friendles" (
  "date" text,
  "opponents" text,
  "venue" text,
  "result" text,
  "score_f_a" text
);
SELECT "opponents" FROM "pre_season_friendles" WHERE "score_f_a"='3–0' AND "date"='31 july 2007';