Been reading a book on grammar.
1. Predicate Nominative is a noun or pronoun which is 1) located in the predicate (the sentence from the verb onward), 2) usually follows the verb “to be,” and 3) always renames the subject. Other names for the predicate nominative are subjective complement and predicate noun. When a pronoun is serving as a predicate nominative it must be in the nominative case.
Ex: It is I. That was Jane. This is him. That must have been he.
2. Object of a Preposition must be in the objective case. Pronouns serving as objects of the preposition must be objective case.
Ex: Incorrect – Between you and I this should be an easy game.
Correct – Between you and me this should be an easy game.
3. Subject of an infinitive is always in the objective case. Pronouns used as subjects of an infinitive must be in the objective case.
Ex: Incorrect – It was I who he wanted to come.
Correct – It was I whom he wanted to come.
4. A noun/pronoun used in apposition takes the case of the noun/pronoun with which it is in apposition.
Ex: Incorrect – The winners, Jack and her, treated the losers, they and we.
Correct – The winners, Jack and she, treated the losers, them and us.
5. If a gerund is modified by a noun or pronoun, the noun or pronoun needs to be in the possessive case if it stands for a person.
Ex: Incorrect – Mother objected to Jack talking.
Correct – Mother objected to Jack’s talking.
6. Maintain consistent use of tense.
Ex: Incorrect – Last year when I am up in town, she tells the boss a lie.
Correct – Last year when I was up in town, she told the boss a lie.
7. Don’t confuse the present perfect with the imperfect (past).
Ex: Incorrect – Did Jackie bring the car back yet?
Correct – Has Jackie brought the car back yet?
8. Errors in use of subjunctive mood. Correct usage is 1) with the expression of a wish or 2) to express a condition contrary to fact.
Ex: Incorrect – I wish I was as tall as my brother.
Correct – I wish I were as tall as my brother.
Incorrect – If Jackie was here now, she would show you how to cook.
Correct – If Jackie were here now, she would show you how to cook.
9. False conditional – If the conditional mood is to be used correctly, a condition contrary to fact must be involved. If no such condition is really present, the you have a false conditional.
Ex: Incorrect – Every day when I arrived, she would be in her chair.
Correct – Every day when I arrived, she was in her chair.