Subject and Object pronouns

Pronouns are words that take the place of nouns.
Example:  Mary is a nice girl.  Mary has a cat.  Mary's cat likes Mary.
After the first use of Mary, we can use pronouns.
Mary is a nice girl.  She has a cat.  Her cat likes her.
This lesson will show you how to use subject pronouns and object pronouns.

Subject Pronouns

Subject pronouns are pronouns that take the place of a subject.  Subjects are usually in front of the verb.  Subjects are the part of sentence that do the action.  The subject pronouns are I, you, he, she, it, they, and we.
Examples:

• I am happy.
• She runs fast.
• He lives in Long Beach.
• We are in class.
• They work at the college.

In these examples, I, she, he, we and they are the subject of the sentence.  They are subject pronouns.
 

Object Pronouns

Object pronouns are pronouns that thake the place of an object.  Objects are usually behind the verb.  Objects are the part of the sentence that receive the action.  The object pronouns are me, you, him, her, it, them and us.
Examples:

• Bring me the book.
• Give her the money.
• Juanita lives close to him.
• The car almost hit us.

http://www.usingenglish.com/quizzes/73.html

http://www.eflnet.com/tutorials/subobjpronouns.php