Possible Duplicate: Is "is" an auxiliary verb? My Mum's bag is blue. Is is an auxillary verb in that sentence? If not, what part of speech is it?
John is working now. Is the verb 'is' in this example an auxiliary verb?
I was just trying to formulate a sentence in an email, and wanted to reference a third person, inquiring as to which of something that person was referring in the forwarded mail message. Is it: ...