For the nominative absolute, see [§ 345].
Care must be taken not to use an objective form when a predicate nominative is required.
- It is I [NOT me].
- It is we [NOT us] who did it.
- It was he [NOT him] who told us.
- It was they [NOT them] who were to blame.
120. It has several peculiar uses in the nominative.
1. It is used as the subject in many expressions like “It rains,” “It snows,” “It lightens,” “It is cold,” where no definite subject is thought of. In this use, it is said to be impersonal.
Note. An impersonal it also occurs as a cognate object ([§ 108]) in colloquial language: as,—“Hang it!” “Go it!” “He went it.” “He farmed it for a year.” Other examples of the indefinite and impersonal it in various constructions are: “We are roughing it.” “Keep it up.” “You’ll catch it.” “Let it all go.” “He made a poor job of it.” “He made a success of it.”
2. It often serves as grammatical subject merely to introduce the verb is, the real subject of the thought standing in the predicate. In this use it is called an expletive (or “filler”).
- It is he.
- It is Christmas.
- It was a tiresome ride.
In these examples, the subject of the thought (he, Christmas, ride) appears as a predicate nominative.
3. The antecedent of it is often a group of words.