听力原文： The United States says Nigeria and Burma take part in much of the illegal drug sales around the world. The State Department made the statement in its yearly report about international illegal drug control. It says nearly all the illegal drug heroin in the United States comes through Nigeria or Burma. The State Department list also names Iran and Syria as countries that are not trying to stop illegal drug sales and production. Nearly all the illegal drug heroin in the United States come through ______.