It is placed in the indicative mood in our grammars; and go is the principal, and will the auxiliary verb.
“To be is an auxiliary verb:” pronounce auxiliary as though spelled awg-zil-ya-re, and not in five syllables.
When used to form a compound tense, the verb esti is called the auxiliary verb.
The verb substantive, which is also used as an auxiliary verb, has two tenses, a present and a past.
auxiliary verb—A verb used to help to express the meaning of another verb by showing its voice, mood or tense.
The auxiliary verb regularly comes first in a verb-phrase, and may be separated from the rest of it by some other word or words.
Yet some of the leading peculiarities of Italian, the article and the auxiliary verb, do not appear.
Sudah is classed as an adverb, but its most common use is to serve as a kind of auxiliary verb in forming the past tenses.
A pluperfect is similarly formed with the past tense of the auxiliary verb.
When two co-ordinate verbs are of the same tense and mood the auxiliary verb should apply to both.
A “helping” verb that modifies the main verb, as in “Gail can win,” “Gail did win,” “Gail could have won.” A question often begins with an auxiliary verb: “Did Gail win?” “Could Gail lose?” The various forms of the verbs can, have, is, and does frequently act as auxiliaries.