A mother is cooking dinner when she hears her son come back from school…

"How was you English test today?" She asked

"It was easy except I had trouble on this one difficult question"

"What did it ask?" The mother replied

"It asked for the past tense of think"

"What did you answer it as?" The mother says.

"I couldn't really figure it out. I thought and thought and thought and thought, and I finally wrote thunk"