One day, the father lets eight-year-old son send a letter. The son took the letter. The father then remembered he didn't write address and addressee's name on the envelope.
After the son comes back, the father asks him: "You have thrown the letter into the mail box?"
"Certainly."
"You didn't notice that the envelope does not have address and addressee's name on it?"
"I certainly saw nothing written on the envelope."
"Then why didn't you take it back?"
"I thought that you did not write address and addressee, because you wouldn't let me know to whom you send the letter!"
(中国日报网英语点津 陈丹妮 编辑)