Answer:
It is the action in the sentence. A verb tells us that some act has been carried out by the subject.
Teenagers should not be allowed to drive until they are 18.
Note taking and read carefully
If I had to take a guess I believe he means that he is a very smart intelligent history teacher. He is familiar to the topic of history and knows enough to be a teacher, and a very good one at that. I hope this answer helped and I'm sorry if it didn't.