CREATE TABLE "singles_7" (
  "edition" text,
  "round" text,
  "date" text,
  "against" text,
  "surface" text,
  "opponent" text,
  "w_l" text,
  "result" text
);

Question: WHAT WAS THE SURFACE MADE OF WHEN THE OPPONENT WAS GEORGE KHRIKADZE?
SQL: SELECT "surface" FROM "singles_7" WHERE "opponent"='George Khrikadze';

Question: WHAT WERE ALL OF THE RESULTS WHEN THEY PLAYED AGAINST LITHUANIA AND THE SURFACE WAS MADE OF CLAY?
SQL: SELECT "result" FROM "singles_7" WHERE "surface"='Clay' AND "against"='Lithuania';