it, its, it's, it's me

It is a short, necessary word often used in a vague or indefinite way to stand for, or refer to, a variety of things and ideas. The term also appears in expressions that are trite or slangy, such as "to get with it," "be with it," "have if" ("be attractive"),"had it" ("reached the end of endurance or patience"). It is a singular pronoun in the third person; "it don't" and "it weren't" are illiteracies. Its is the possessive form of if."The dog has lost its collar." "I'm sorry about its arriving too late for your birthday." It's means "it is" (It's raining) and "it has" (It's been raining). Awkward and stilted though the expression may sound, one should say "It's I" rather than "It's me," because a predicate complement is in the nominative case. If you don't like to say "It's I" (or "It is I" or "This is I"), then say "This is" followed by your name. Similarly, watch out for such expressions as "It's us," "It's them," "It's her," "It's him." If you think the correct forms of we, they, she and he in these constructions sound strained, then use names: "It's Jane," "It's Jim."