什么是代词,实意动词,助动词,情态动词,定冠词,形容词,副词,连词,介词?

代词就是代替名词、形容词或数词的词.代词可分为八类：人称代词、物主代词、指示代词、反身代词、疑问代词、不定代词、关系代词、相互代词.
列个表出来就容易理解了：
人称 主格 宾格 物主代词 反身代词
形物代 名物代
第一人称 （单）I （单）me my mine myself
（复）we （复）us our ours ourselves
第二人称 （单）you （单）you your yours yourself
(复）you （复）you your yours yourselves
第三人称 he him his his himself
she her her hers herself
it it its its itself
they them their theirs themselves