听力原文： The U. S. Space Agency NASA says Russia's orbiting Mir space station has lost its primary and backup oxygen sources. If the problem is not fixed, the 3 - member crew would have to abort the mission. But, a Russian space official in Moscow told Ruters News Agency that only the primary generator developed trouble and that the unit was repaired by the crow. More about the latest problem on heard the space station from VOA 's Nick Simming. 'The U. S. Space Agency says Mir's two primary sources of oxygen have stopped working and now there is only several days'supply of oxygen inside Mir's cabin. Mir's backup oxygen generating candles failed Monday just after the normal oxygen supply system used by the spacecraft un- expectedly shut down. That normal oxygen source, a method that extracts oxygen from water, had been turned off for several days to conserve energy while Mir's crew performed re- pairs. But when the system was activated Monday, it overheated and automatically shut down. NASA's problem is not fixed soon, the two Russians and one American on board will have to abort. This problem is the most serious to plague the space station which has endured power loses, computer mal- function and even a collision with a supply vessel all in the past six months. Nick Simming VOA News, Washington.' The U.S. Space Agency NASA says ______ orbiting Mir space station has lost its primary and backup oxygen sources.