"Johnny, look at this refrigerator door. We're going to have a catastrophe in here. If you don't fix that shelf, the milk will pour right out on to the floor."
"Huh?"
"Milk! The milk! It'll spill everywhere. Can you hear me?"
"I can't hear you."
"Your hearing aid!"
"I'll have to get my hearing aid."
"I thought you put it in this morning."
"Huh? I forgot to put it in this morning."