change: implies making either an essential difference often amouting to a loss of original identity or a substitution of one thing for another: ~d the shirt for a larger size.      表示本质的变化或者替换，如you can't change human nature人的天性不能改变，如winter changed to/into spring冬去春来，如a change of heart重要的想法的改变，如he had a change of heart about retiring and decided to continue working他改变了退休的想法，决定继续工作     amount to接近几乎


alter: implies the making of a difference in some particular respect without suggesting loss of identity: slightly ~ed the orighinal design.     常用于改衣服，如she had/got the dress altered她让人改了衣服    也可用于较大的改变，如he altered his will to leave everything to his sister改遗嘱把所有留给妹妹，如an event that altered the course of history改变历史进程的事件


vary: stresses a breaking away from sameness, duplication and repetition: you can ~ the speed of the converyor belt.     I try to vary my diet避免饮食单一   传送装置conveyor之前错写成er


modify: suggests a difference that limits, restricts,  or adapts to a new purpose: ~ied the building for use by the handicapped.    表示部分改变，如modified a plan部分改变(即调整)计划，如he modified the recipe by using oil instead of butter调整配方用油替代奶油，we played a modified version of the game规则部分改变的游戏版本       语法上指修饰限制to limit or describe the meaning of a word or phrase，如adjectives usually modify nouns, and adverbs usually modify verbs, adjectives, and other adverbs形容词修饰名词，如in "a red hat", "red" is a modifier describing "hat" red是hat修饰语


change改变: 表示本质改变(导致身份丧失loss of identity)或完全替换, alter变化: 指改变某方面，但身份不变, vary变化: 强调变得不相同雷同重复，modify修改、修饰: 指改变一部分保留其它不变，或修饰


记忆方法: 1) 首字母CAVM变为CAVE(洞穴)<==改变最后一个字母

         2）练习一下

         3) 改变的意思是使不同mean to make or become different.首字母CAVM变为CAVE(洞穴)<==改变最后一个字母