人称代词里的：主格放在句首做主语和表语,宾格放在句末或句中做动词和介词的宾语.
打个比方,主人邀请宾客,主格就像主人,宾格就像宾客.主格在动词前面,宾格在动词或介词后面.
英语中的人称代词(Personal Pronouns)有主格、宾格和之分,如：
I,me,my ; he,him,his ; they,them,their等.
顾名思义,主格(The nominative case)用作主语,宾格(The objective case)用作宾语,所有格(The possessive case)则表示所有之物.
在实际运用中,主格和宾格代词有时会混淆.下面是常见的问题：
⒈在复合结构里,人称代词的主格和宾格在单独使用时,没有问题,如很少人会犯下这样的错误：
*(1)Wilcox spoke to I.
*(2)Her knew what had happened.
但在复合结构中,错误就难免了,如：
*(3)Wilcox spoke to my friend and I.
*(4)He and her knew what had happened.
*(5)This is between you and he.
这种错误是可避免的.第一,在有介词的复合结构中,特别要注意,第二个人称代词,必须用宾语,如："for you and me"和 "between Maria and him".第二,试把复合结构中的另一部分暂时用括号围起来,那么该用的格就容易辨别了,如：
(6)This message is for (My father and) I or me.
(7)(Marry and) he or him went downtown together.
显然的,(5)里的代词是宾格的"me",(6)里的代词是主格的"he".
⒉在比较结构里,连接词"as"或"than"后面,按理用主格式,但在口语中,人们常用宾格形式,学美式英语者,更是如此：
(8)a.You did as well as she.
b.You did as well as her.
(9)a.I am older than he.
b.I am older than him.
(a)和(b)两种说法,都可接受.但如果"as"和"than"后头分句的主语和词动都要完整出现的话,这时的人称代词,就必须是主格,如下：
(10)You did as well as she did.
(11)I am older than he is .
此外,还有一点要注意,就是"as"和"than"后面虽然在语法上用主格好,用宾格也可,但是有时意思会有所不同.试比较(a)和(b)：
(12)a.Jason praised Maria more highly than I.
b.Jason praised Maria more highly than me.
(12)a和b都被接受,但(12)a等于(13)a,而(12)b等于(13)B：
(13)a.Jason praised Maria more highly than I did (= I praised Maria).
b.Jason praised Maria more highly than he praised me.
显然,这两句的深层意思大有差别.遇到这种情形,为了避免误解,不妨根据要表达的意思用完整的句式表达出来.换句话说,必要的话,要用(13)这句子.
不然,把(13)a变成(14),(13)b变成(15)也可：
(14)I did not praise Maria as highly as Jason did.
(15)Jason did not praise me as highly as he praised Maria.