A fourth-grade teacher was giving her pupils a lesson on logic.

　　"Here is the situation," she said. "a man is standing up in a boat in the middle of a river, fishing. He loses his balance, falls in, and begins splashing and yellin 
g for help. His wife hears the commotion, knows that he can't swim, and runs down to the bank. Why do you think she ran to the bank?"

　　A girl raised her hand and asked, "to draw out all of his savings?"