[originaltext]　　(3) The United States says it will provide an additional 180 mi

　　(3) The United States says it will provide an additional 180 million dollars to help feed the people of South Sudan who are threatened by famine. The White House urged the country’s president and its former deputy to assume their responsibilities and prevent further needless suffering. Chris Stillwalker from BBC in the United States reports. "This rises to more than 600 million dollars, added to the amount of the United States. (4) The White House says the South Sudanese are suffering because of the inability of the country’s leaders to put their people’s interests above their own. The power struggle between its President Salva Kiir and his ex-deputy Riek Machar has plunged the country into renewed warfare, leaving thousands dead and nearly two million refugees."
　　3. What happened to the people of South Sudan?
　　4. According to the White House, why are the South Sudanese suffering?