I know him, I don’t know him

Mr. B walked a kindergarden student to his room where I was working as the guest teacher for the day.  The 6 year old was surprised to see me and not his usual teacher.  Mr. B asked the student, “Do you know Mr. Fleming?”

“Yes, I know him.”

“Are you ready to have a good day with him, learn a lot and follow the instructions he gives?”

“Well, I’m not sure.  He’s old.  And I don’t know him.”