Written on the board: A predicate nominative renames the subject.
The question on the Latin worksheet: A ________ ________ renames the subject.
Z: "I don't know the answer."
Mommy: "Look at the board."
Z (looks at the board): "A who what?"
Mommy: "No. Read what is on the board."
Z (studies the board): "I don't know."
Mommy: "Read the sentence on your paper and read the board."
Z (studies me): "You look frustrated."
At this point I should get some sort of award for not yelling "Yes, I am frustrated!! We just spent 20 minutes talking about this. The exact same sentence is written on the board with the answer you need, for Pete's sake!!!! Apply yourself!
Mommy: "You cannot get out of your chair until you get the right answer."
Z (looks at his paper and then the board): "Uh, is it predicate nominative?"