困: sleepy, tired...
正直: upright, upstanding, honest...
及格: to pass an exam or a test, to meet a minimum standard...
关节: joint (physiology), key point, critical phase...
国外: abroad, external (affairs), overseas, foreign...
弄虚作假: to practice fraud (idiom); by trickery...
界线: limits, bounds, dividing line...
