CREATE TABLE table_67642 ("Name" TEXT, "Height of bridge structure" TEXT, "Longest Span" TEXT, "Type" TEXT, "Opened" FLOAT, "Location" TEXT)

How tall is the Anqing Bridge which opened prior to 2011?
SELECT "Height of bridge structure" FROM table_67642 WHERE "Opened" < '2011' AND "Name" = 'anqing bridge'
SELECT "Height of bridge structure" FROM "table_67642" WHERE "Name" = 'anqing bridge' AND "Opened" < '2011'