“Are” is not an adverb

“No, ‘are’ is an adverb,” the student said. Then she began to frantically leaf through a stack of notes, convinced her English teacher had said this. She is in high school.

I don’t fault the kid. I don’t fault her teachers, either. I strongly suspect any responsibility lies with the curriculum that ducked grammar and verbs, leaving this girl lost at sea in her foreign language class.