《颜氏家训·勉学篇》
除此之外大多数是田野村夫，言语鄙陋，举止粗俗，还非常的固执己见，什么能耐也没有，问一句就得回答几百句，词不达意，不得要领，邺下有俗谚说： 博士买驴，写了三大张契约，全篇没有一个 驴 字。 
以外率多田野间人，音辞鄙陋，风操蚩拙，相与专固，无所堪能。问一言辄酬数百，责其指归，或无要会。那下谚云： 博士买驴，书卷三纸，未有 驴 字。 
Besides, most of the others were farmers and villagers with vulgar language and rude behavior. They were also very stubborn and incapable. Ask them a question, they could give hundreds of answers which were irrelevant and incomprehensible. There was a popular saying in Yexia: A Doctor of Letters bought a donkey and wrote three large sheets of contract, but the word “donkey” was nowhere to be found in the whole article.