The primary verb to be is exceptional. It is unique among English verbs in having eight different forms, and as in most European languages, it presents difficulties of idiomatic usage and of grammatical correctness (for one of the commonest difficulties, see been - being - bean).
To be is used as an auxiliary to communicate various grammatical categories. The be-progressive, used with an -ing participle ("He was eating a cake"), communicates aspect, and the be-passive used with an -ed participle, ("He was eaten by wolves"), communicates voice. The two uses can be combined to form the passive progressive: "He was being eaten by wolves".
One other peculiarity - in its semantic role (its meaning) - should be mentioned. to be is the only verb with its own name. It is known as the copula. This (a Latin word meaning 'a bond or tie'; see -cule) refers to its unique function of equating two things - of saying that a person, for example, is something, a nationality, a profession, or in an aesthetic state, etc: "He is Scottish", "They are teachers" or "she is beautiful". 'To be' can also be used, if less commonly, as an absolute lexical verb meaning 'exist', or 'to have being': we can say "God is"; and Hamlet, contemplating suicide, famously says "To be or not to be: that is the question" (Hamlet, III i) (i.e 'should I continue to exist, or stop existing?', 'should I live or kill myself?').
It is this verb above all that gives difficulty to the old Primary school definition of a verb as 'a doing word'. It is why the Secondary definition of 'a word that expresses an action or a state' is necessary, because possibly the most common single verb in English does not express 'doing'. When we say "John is a nurse" we do not mean that he is doing anything. We are trying to describe his state, not to say what action he is performing.
There are a few similar verbs known as copulative verbs, such as 'to seem' ("She seems sad" is roughly equivalent to "She seems to be sad") and 'to become'.
The eight different forms of to be are:
- in the indicative:
- As a general rule, the subjunctive is
- and there are two participles, been and being.