Who and Whom
That whole 'object of a preposition' thing also applies when you need to figure out whether to use 'who' or 'whom' in a sentence. Now, the reality is unless you really love grammar (and some of you do, like Gary, our Grammar Gorilla . . . Where is Gary?), the reality is that you rarely use the word 'whom' when you're speaking or writing informally. But for formal writing, you should at least know when to use it before deciding that you think it's too stuffy or uptight (and your teacher might require you to use it).
Okay, so, just like 'which,' use 'whom' whenever a preposition precedes the word. In other words, the correct grammatical construction is always 'for whom' and never 'for who', likewise 'for whoever' and 'for whomever.' You'll also want to use 'whom' or 'whomever' whenever it's the object of the verb of a sentence or clause in general.
Gary, whom I barely knew, was missing.
'Whom I barely knew' is a non-restrictive clause, with 'I' as the subject, 'knew' as the verb and 'whom' as the object of that verb (referring to Gary). When not used as an object, however, the correct pronoun is 'who,' as in:
Gary, who forgot to ask to be paid up front, was in a predicament.
Interrogative Pronouns
'Who,' 'whom,' 'whose' and 'which' can also function as interrogative pronouns, along with 'what.' Simply put, an interrogative pronoun, despite sounding kind of fancy, is just a pronoun that helps ask a question. As in, Whose collectible action figures are these? or To whom am I speaking? Use 'which' when referring to a specific range of options, as in, Which of these keys opens the gorilla cages? Use 'what' when there's a broader world of possible answers, as in What is that guy in the gorilla suit doing in that cage? To which you might respond 'Who?' Those are interrogative pronouns.
Possessive Pronouns
Possessive pronouns, like they sound, are pronouns that show possession. You'll recognize them right away. They are: 'my,' 'mine,' 'your,' 'yours,' 'his,' 'hers,' 'our,' 'ours,' 'their,' 'theirs' and 'whose'. You probably know how to use these already, but there are a couple of grammar points that can trip people up.
When used alone, choose from 'mine,' 'yours,' 'his,' 'hers,' 'ours,' 'theirs' and 'whose.' As in The responsibility for proper gorilla upkeep is theirs.
'My,' 'your,' 'his,' 'her,' 'our,' 'their,' 'whose' and 'its' should be used when the possessive is modifying a noun. As in 'This is my shoot!' the director yelled.
Now, when a pronoun precedes a gerund - which, if you remember from a previous lesson, that's a verb that acts as a noun, typically ending in -ing - you should use a possessive pronoun, not a regular personal pronoun. Treat it just like a possessive pronoun modifying a regular noun because that's what a gerund is; it's a verb that's acting as a noun. That sounds easy, but it's a common mistake, especially with the pronoun 'you.' Let me give you an example here.
'Sorry, Gary, we didn't hear you screaming,' the director said. should be Sorry, Gary, we didn't hear your screaming.
Reflexive Pronouns
Reflexive pronouns 'reflect back' on the subject of a sentence or clause. They're actually pretty simple. The reflexive singular pronouns are 'myself,' 'yourself,' 'himself,' 'herself' and 'itself,' while the plural reflexive pronouns are 'ourselves,' 'yourselves' and 'themselves.' I'm not going to spend a lot of time on this as you use these all the time, and there's nothing too tricky about them. Just remember to use plural reflexives when they refer to plural subjects and singular reflexives when they refer to singular subjects.
So, The cast couldn't stop themselves from laughing when they realized Gary's dilemma. is a proper use of the reflexive. As is Gary promised himself never to take an acting gig from a Study.com instructor again.