Database: world_1
Question: What are the names of nations where both English and French are official languages?
SQL: select t1.name from country as t1 join countrylanguage as t2 on t1.code  =  t2.countrycode where t2.language  =  "english" and t2.isofficial  =  "t" intersect select t1.name from country as t1 join countrylanguage as t2 on t1.code  =  t2.countrycode where t2.language  =  "french" and t2.isofficial  =  "t"