every是形容词,只能作定语修饰单数名词,意思是“每一个”,表示整体概念；
each是形容词、代词,可用作主语、宾语、定语等,意思是“每个”或者“各个”,表示单个概念；
each可以放在名词前,可以后跟of短语,与动词同时出现时要放在“be动词、助动词、情态动词”之后或者行为动词之前。
every和each都用作单数理解,但是在下文中既可以用单数的代词(如he/him/his)也可以用复数的代词(如they/them/their)替代。
如：
Every one of the students in his class studies very hard.(他班上每个学生学习都很用功。)
They are very busy. Each of them has something to do.(他们很忙,人人都有事干。)
