Editing Copula (linguistics) (section)

==== Auxiliary verb ====
The English verb ''[[wikt:be#Verb|to be]]'' is also used as an [[English auxiliaries|auxiliary verb]], especially for expressing [[passive voice]] (together with the [[past participle]]) or expressing [[progressive aspect]] (together with the [[present participle]]):

{{Poem quote|
The man '''was''' killed. (passive)
It '''is''' raining. (progressive)
}}

Other languages' copulas have additional uses as auxiliaries. For example, French {{lang|fr|être}} can be used to express passive voice similarly to English ''be''; both French {{lang|fr|être}} and German {{lang|de|sein}} are used to express the [[Perfect (grammar)|perfect forms]] of certain verbs:

{{Poem quote|{{lang|fr|Je '''suis''' allé(e)}} French for {{gloss|I went}} and {{gloss|I have gone}}, literally {{gloss|I am gone}}, but does not imply still being gone.}}

In the same way, usage of English ''be'' in the present perfect, though archaic, is still commonly seen in old texts/translations:

{{Poem quote|
I '''am''' become death.
He '''is''' risen.
}}

The auxiliary functions of these verbs derived from their copular function, and could be interpreted as special cases of the copular function (with the verbal forms it precedes being considered adjectival).<!-- This sentence needs revision in order to be readily comprehended. -->

Another auxiliary usage in English is to denote an obligatory action or expected occurrence: "I am to serve you". "The manager is to resign". This can be put also into past tense: "We were to leave at 9". For forms such as "if I was/were to come", see [[English conditional sentences]]. (By certain criteria, the English copula ''be'' may always be considered an auxiliary verb; see [[Auxiliary verb#Diagnostics for identifying auxiliary verbs in English|Diagnostics for identifying auxiliary verbs in English]].)