Pronouns are words that take the place of nouns. There are various ways they can be used depending on whether the pronoun is the subject or object or is reflexive. For example:
Subject pronouns are: I, you, he, she, it, we, they.
Object pronouns are: me, you, him, her, it, us, them.
Reflexive pronouns: myself, yourself, himself, herself, itself, ourselves, yourselves, themselves.
Now we have split the pronouns into groups, we can look at the rules of use.
When you use a subject pronoun (which is also known as nominative case), it can be the subject of a sentence, for example, "I am a student", "Jane and he are colleagues" but when the pronoun is used after the verb "to be", the pronoun renames the subject. The "to be" verbs are as follows: is, are, was, were, will be, may be, may have been. Here is an example of a pronoun used after a "to be" verb:
"It is I who wrote the letter." Here, "I" comes after the "to be" verb "is" and the subject is renamed "it". So, the subject pronoun needs to be used instead of the object pronoun.
We use an object pronoun (also known as objective case) when the pronoun is the direct object (not the subject), the indirect object or the object of the preposition.
Here are some examples:
"John met her at the library." Here, "her" is the direct object.
"Sue will give him his book back." In this example, "him" is an indirect object because you can, in your mind, put the word "to" in front of "him" (Sue will give to him). In this case, "book" is the direct object. Let's look at other examples:
"Between you and me, this book is terrible." In this case, "you" and "me" are the objects of a preposition (between).
Lastly, we shall turn to reflexive pronouns. For example, you can write "She did it herself" but you would never write or say "Give the book back to John or myself". In this last sentence, "myself" does not refer back to another pronoun or noun - the correct pronoun is "me" (an object pronoun).
As you can, there are lots of different ways to use pronouns and it is important to use them correctly when speaking or writing.
