1. 主格和宾格
1) 通常，人称代词主格用做主语或表语;宾格用做动词或介词的宾语。句子的结构如有变化，也应能加以分析，确定选用哪种形式。例如：
It was he who told a lie.
It’s not me (who / whom) he wants. (作宾语)
This is a secret;it's between you and me.(作介词宾语)
2) 人称代词宾格可用在比较状语从句一类的结构中代替主格。例如：
He is taller than me / I (am). I don't swim so well as her / she (does).
2. 两种所有格
人称代词所有格称为物主代词。物主代词分为两类：
① 形容词性的，如my, her, your, their等;
② 名词性的，如mine，hers，yours，theirs等。由于受汉语影响，我们常犯以下两种错误：
1) 漏用代词，主要是形容词性的物主代词，因为汉语中常常将它省略。例如：
I have done my homework.(不能说 * I have done homework.)
We clean our classroom every day.(不能说 * We clean classroom every day.)
2) 误用代词，混淆两种类型的物主代词，因为汉语中无此区别。例如：
That dictionary is not mine.(不能说 * That dictionary is not my.)
Mine is here.(不能说 * My is here.)
注意：形容词性的物主代词只能用作定语，必须与名词连用。例如
What's her name? I am your friend.
名词性的物主代词则可充当名词所能充当的各种句子成分。如：
Your pen is black;mine is blue.(作主语)
You haven't got a bike?You may use mine.(作宾语)
但是its一般不能单独使用。需要时可以用its own。如：
That's the cat's basket. It's its own.
3. 代词做短语动词宾语时的位置
当短语动词由“动词+副词”构成时，代词作宾语必须放在动词和副词中间，名词则不受此限制。如：
He looked up the word in the dictionary. He looked the word up in the dictionary.
He looked it up in the dictionary.
但如果是由“动词+介词”构成的介词动词，代词作宾语还是要放在介词之后。例如：
He's been looking for them all this morning.
