1. Unit 2: Case

2. Subject and Object Errors
Nouns & Pronouns have 3 CASES:
Subjective: The garden is large.
Objective: David weeded the garden.
Possessive: David’s garden is large.

3. Nouns are easy. Pronouns, because they take different forms in the subjective and objective forms, prove challenging.
Subjective Pronouns:
Objective Pronouns:
Possessive Pronouns: I He
She We
They
Who
Whoever Me
Him
Her Us
Them
Whom
Whomever My
Your
His
Its
Our
Their
Whose

4. Advice: Identify the subject of the clause in order to find the proper pronoun case. It becomes difficult when the verb or preposition is separated from the object, so you’d better believe that the PSAT will exploit this difficulty!
Find the errors:
I am going to the play with her.
Me and her are going to the games. 
The judges gave prizes to my brother, sister, and I. 
For we Americans, July fourth is a special day. 
Mary invited my cousin, her sister, a friend from New York, and I to the party.  

5. Pronouns in Apposition
An appositive is a word, phrase, or clause placed next to another word, phrase, or clause in order to explain it.
Margaret, my sister, and my oldest brother, Hugh, are in New York.
Be careful with pronouns in apposition. They must take the same case as the nouns they replace.
The outfielders, Jack, Joe, and (I, me) are ready to play.
The class elected three representatives, Jack, Joe, and (I, me).

6. Who and Whom: (Arggg!)
Always ask: Should the pronoun be a subject (who) or an object (whom)?
Advice: Replace who/whom with he/him.
(Who, Whom) is going to the store?
(Who, Whom) are you going with?
(Who, Whom) did they choose?

7. [Clause: A group of related words containing a verb and its subject.]
For “nastier” examples of who and whom sentences, break the sentence down to its individual clauses.
[Clause: A group of related words containing a verb and its subject.]
He will give the book to (whoever, whomever) wants it.
He will give the book to (whoever, whomever) Jane chooses.
[Ignore parenthetical statements which interrupt clauses (I think, they believe, he supposes, they say). They are their own clauses that do not take objects.]
They will pay a large fee to (whoever, whomever) they decide is most qualified.

8. Possessive Case Errors
Use a possessive noun or pronoun before a gerund. A gerund is a verb used as a noun, and is formed by adding an –ing to the verb stem. 
I don’t like my (brother, brother’s) borrowing so much money.
I don’t mind (him, his) eating so much ice cream.
I don’t approve of (him, his) driving with such worn-out tires.
I recommend (him, his) seeing a doctor.