inconstant: implies an incapacity for steadiness and an inherent tendency to change: the supply of the material was too ~ to rely on.       (steady稳定: 指规律无波动无间断implies regularity without fluctuation or interruption，如ran the race at a steady pace比赛中以稳定的速度跑步, 如slow and steady wins the race虽然慢但不停歇(稳定)的人赢得比赛，是龟兔赛跑的寓意。stable也是稳定，表示牢固平稳不容易翻倒移除deep-rooted or balanced or established, and therefore resistant to be overthrown or displaced，如stable ladder/work/government/relationship/condition稳定的梯子/工作/政府/关系/病情(即不再恶化)。 两个稳定容易混，steady偏指动作，stable偏指情况状态，例如英语中既有steady person的用法也有stable person的用法，需要根据上下文判断是动作步伐稳定还是情况状态稳定）  （tendency倾向于，等于中文中的容易，但英文中不说easy容易而是用tend或incline倾向于，两个词互相解释，本句也可以说...inclination to change）

fickle: suggest unreliability because of perverse changeability and incapacity for steadfastness: performers discover how ~ the public can be.   perverse（不讲道理的）执拗固执     （steadfast坚定的：指坚持某一"道路"如爱情效忠支持信念love, allegiance, support, conviction，如Romeo and Juliet were steadfast in their love罗密欧与朱丽叶的爱情忠贞不渝）


capricious: suggests motivation by sudden whim or fancy and stresses unpredictability : an utterly ~ manner of selecting candidates.   （whim一时兴致突发奇想a sudden wish，如an old antique bought on a whim心血来潮买下了古董）   （fancy幻想满足愿望imagination spurred by desires，如fancied herself a super star幻想成为超级明星）


mercurial: implies a rapid changeability in mood, especially between depression and elation: so ~ in temperament that no one knew what to expect.    (depression不是一般的压抑而是抑郁，不仅压抑而且难以恢复，如depressed to the point of suicide抑郁到自杀)  （elation兴高采烈great happiness and excitement,如his supporters have reacted to the news with elation他的支持者听到那条消息后兴高采烈）


unstable: implies an incapacity for remaining in a fixed position or on a steady course, when applied to persons, suggests a lack of emotional balance: in love she was impulsive and ~.


inconstant不稳定: 指不稳定易变化，fickle多变: 表现反常地多变不可靠，capricious任性随意: 表示突然改变想法愿望,难以预测，mercurial情绪多变: 表示情绪变化很快，特别是从抑郁到欢喜，unstable不稳定: 指位置状态等不稳定，形容人时可以表示精神不稳定。


记忆方法: 1）首字母IFCMU排列成FroM ICU来自ICU<==情况不稳定      （the patient's condition is unstable ）


         2）不定的意思是目的或投入等不坚固不稳定mean lacking firmness or steadiness in such things as purpose or devotion.