CREATE TABLE table_17506 ("Year" FLOAT, "Mens singles" TEXT, "Womens singles" TEXT, "Mens doubles" TEXT, "Womens doubles" TEXT, "Mixed doubles" TEXT)

Who won the Men's Doubles when Guo Xin won the Women's Singles?
SELECT "Mens doubles" FROM table_17506 WHERE "Womens singles" = 'Guo Xin'
SELECT "Mens doubles" FROM "table_17506" WHERE "Womens singles" = 'Guo Xin'