John is working now.
Is the verb 'is' in this example an auxiliary verb?
John is working now.
Is the verb 'is' in this example an auxiliary verb?
Yes, as described in Wikipedia
The auxiliary verb be is used with a present participle to form the progressive aspect; for example, "I am riding my bicycle"
An auxiliary verb is a verb used in forming the tenses, moods, and voices of other verbs.
In English, such verbs are be, do, and have.
Yes 'is' is an auxiliary verb to show the present continuous form of tense in the sentence you have quoted.