Pronouns

A pronoun is a word that takes the place of a noun. There are subject, object, possessive, and reflexive pronouns.
Rule 1

Subject pronouns are used when the pronoun is the subject of the sentence.

• I
• You
• He
• She
• It
• We
• They

Rule 2

Subject pronouns are also used if they rename the subject. They follow to be verbs such as is, are, was, were, am, and will be.

• It's he.
• This is she.
• It could have been they. 

Rule 3 

Object pronouns are used everywhere else (direct object, indirect object, object of the preposition). 

• Me
• You
• Him
• Her
• It
• Us
• Their

Rule 4

To decide whether to use the subject or object pronoun after the words than or as, mentally complete the sentence.

Paul is as smart as she / her. She is trhe correct answer because the appropriate idea is "Paul is as smart as she is".

Daniel would rather talk to I / me. Me is the correct answer beacuse the pronoun is the object of the preposition to.

Rule 5

Possessive pronouns show ownership and never need apostrophes.

• Mine
• Yours
• His
• Hers
• Its
• Ours
• Theirs

Do not confuse possessive pronouns with possessive adjectives. Remember that a pronoun substitutes a noun. 

• Tom's car is blue. Mine is gray. (Mine is a possessive pronoun)
• Tom's car is blue. My car is gray. (My is a possessive adjective)

Rule 6

Reflexive pronouns are used when the subject and object of the sentence is the same person.

• Myself
• Yourself
• Himself
• Herself
• Itself
• Ourselves
• Yourselves
• Themselves