听力原文： U. S. -led coalition forces in Afghanistan say American and Afghan troops have rescued 5 civilian contractors, pinned down by Taliban militants after their helicopter landed in Gazni province south of Kabul. A statement said U.S. special forces and an Afghan police rapid reaction team rescued the contractors late Thursday after receiving a distress call. It said coalition troops killed three Taliban militants, who opened fire on a helicopter when it made an emergency landing due to mechanical problems. The coalition statement did not mention the nationalities of those rescued or the company they worked for. Who rescued those civilian contractors?