听力原文： The former chief accountant of the failed energy giant Enron has pleaded guilty to a single charge of securities fraud under a plea bargain. It's thought the deal could lead to the accountant Richard Causey giving vital evidence against the company's founder Kenneth Lay and the former Chief Executive Jeffrey Skilling. Enron was one of the ten biggest companies in the United States before its collapse 4 years ago. Thousands lost their jobs and investors lost billions of dollars when it went bankrupt. 15 former executives have since pleaded guilty to a range of charges, and agreed to cooperate with prosecutors, 3 men refused. Richard Causey was among them. And until now he's put up a united front with the company's founder Kenneth Lay and the former Chief Executive Jeffrey Skilling. The prospect of decades in jail is believed to have prompted him to change his plea and turn on his former colleagues in anticipation of a lighter sentence. Richard Causey has turned on his former colleagues in hope of ______.