新闻中提及Earlier Friday, Mr. Obama talked with Haitian President Rene Preval, after several days of efforts to reach his counterpart on the telephone，可知在周五之前奥巴马都没能联系上海地总统，因此 周五的这次联系是地震后两位总统的首次通话。

【听力原文】
President Obama says the United States will fully back Haiti' s rescue and recovery efforts, now and in the future. Earlier Friday, Mr. Obama talked with Haitian President Rene Preval, after several days of efforts to reach his counterpart on the telephone. Mr. Preval lost his home when the presidential palace and government ministries collapsed in the quake.