听力原文： The front-runner in the presidential election in Haiti Rene Preval has accused the electoral authorities of committing fraud in an attempt to stop him winning outright. With almost all the votes counted, Mr. Preva1 is just short of the majority needed to avoid a second round. Two people were killed during unrest in the city. The United Nations Security Council has called for calm and extended the mandate of its peace mission in Haiti by six months. According .to official election figures with around 90 per cent of the votes counted, Rene Preval is just short of the 50 per cent he needs to avoid a second round runoff. Speaking in the Haitian capital Port-au-Prince, he said he'd seen gross errors and probably gigantic fraud. Claiming a first round victory, he urged his supporters to keep up protests, but he also called them on to be mature, responsible and non-violent. If Rene Preval's supporters exceeded 50% of the total voters, he would