Fortitude indefatigability perseverance persevere tenacity.不屈不挠....

n.不疲劳，不屈不挠...

n.易疲劳性...

At this time , the gastrointestinal manifestations, together with extreme weakness and fatigability, are the major symptoms.复发时, 胃肠道症状, 同时伴有极度虚弱和乏力, 为主要临床表现....

indefatigability的音标：indefatigability的英式发音音标为：[ɪndɪfætɪɡə'bɪlɪtɪ]indefatigability的美式发音音标为：[ɪndɪfætɪɡə'bɪlɪtɪ]...

fatigability的音标：fatigability的英式发音音标为：[fætɪgə'bɪlətɪ]fatigability的美式发音音标为：[fætɪgə'bɪlətɪ]...