CREATE TABLE "table1_1337525_1" (
  "complete_series" text,
  "region_1" text,
  "region_2" text,
  "region_4" text,
  "dvd_extras_and_bonus_features" text,
  "number_of_discs" real
);

Question: What is the region 2 for the complete fifth series?
SQL: SELECT "region_2" FROM "table1_1337525_1" WHERE "complete_series"='The Complete Fifth Series';

Question: What is the number of region 4 for the series of the complete seventh series?
SQL: SELECT COUNT("region_4") FROM "table1_1337525_1" WHERE "complete_series"='The Complete Seventh Series';

Question: What is the region 1 where region 4 is tba is the complete eighth series?
SQL: SELECT "region_1" FROM "table1_1337525_1" WHERE "region_4"='TBA' AND "complete_series"='The Complete Eighth Series';

Question: Name the region 4 for the complete fifth series
SQL: SELECT "region_4" FROM "table1_1337525_1" WHERE "complete_series"='The Complete Fifth Series';