object pronouns and subject pronouns一問

Subject pronoun (I, You, We, They, He, She, It) 通常用在句子開頭
Object pronoun (me, you, us, them, him, her, it) 通常用在句子尾

e.g. I clean the blackboard.
The blackboard is cleaned by me.
以上兩句意思相同, 但第一句用了主動式, I 是句中的subject, the blackboard是object。
第二句用了被動式, 今次the blackboard 是 subject, 而me是object, 由於 I 是subject pronoun, 不能用作object, 所以要用object pronoun -- me代替。

e.g. Susan played with Tom and Mary yesterday.
如果我要用pronoun取代以上的人名, 可以這樣表示:
She played with them yesterday. 並非 She played with they yesterday.

Tom and Mary 因為是句中的object, 所以要用them, 不是they; 同樣, susan是句中的subject, 所以會用she, 不是her.

希望你明白啦!!