indefatigable: implies persistent or unremitting activity or effort: an ~ champion of women’s rights.    （unremitting不停的not stopping, 如unremitting hostility/misery/gloomy weather从未化解的敌视/一直很悲惨/持续的阴沉天气）


tireless: implies a remarkable energy or stamina: honored as a teacher of ~ industry and limitless patience.   (stamina耐力，指长时间做事的能量力量energy or strength to do something for a long time，如it takes a lot of stamina to run a marathon跑马拉松需要耐力)


untiring: implies the extraordinary ability to go on continuously and without interruption: ~ researchers who fight against the disease.


unwearied: stresses the apparent absence of any sign of fatigue in the person or thing concerned: detectives remain ~ in their search for the killer.  （fatigue疲倦指劳累到无精打采的地步to tire to the point of listlessness，如fatigued by the long climb长时间爬山后疲倦，中文中”倦”表示想睡觉休息，疲倦比疲乏程度重疲乏只是缺乏体力精力，但比疲惫程度轻如疲惫不堪，疲劳则用来表示”劳累”如疲劳驾驶）


unflagging: stresses the absence of any diminution or relaxation in one’s efforts or powers: an ~ attention to detail.  （diminish明显减小perceptible loss，如his muscular strength diminished with age随着年龄增长他肌肉力量明显减小）


indefatigable坚持不懈的: 指长期不停地努力，tireless不倦的: 指有能量耐力，untiring奋斗不息的: 指超常的连续不断地努力，unwearied不倦的:  表示没有任何疲倦的迹象，unflagging不松懈的: 表示不减小不放松


记忆方法: 1）首字母ITUUU你们三个IT人<==不知疲倦      有些IT员工被强制996工作制，好像要不知疲倦


         2）不倦的意思是能长期艰苦地努力mean capable of prolonged and strenuous effort.  (strenuous艰苦的hard and challenging, 如
 strenuous climb/life in the Gebi desert艰难的攀登/戈壁中的艰苦生活)


        3）这组词不好分辨不好记。先把方法1的首字母记下来，这样在任何地方都能很容易记起来这几个词。之后回想每个词的意思和例句，还有标红标蓝的关键词，红表示"是"蓝表示"否"。几个小时后再重复一两次，一般就可以牢记、熟练使用了。 其它简单的词条，这么记也是最高效的。