与时俱进！我孩子这两年考过这几类奥赛，所以门儿清。：）

都不容易。想进前二十啊，前二十七的，都得掉身皮。Who cares about your skin color before that?? Even Green Card holders or non-citizens can repsent U.S in international competitions! The only requirement: you must have a valid visa (for international travel purposes)!