at one time einstein traveled all over the united states givinglectures.he traveled by car and soon became quite friendly withthe driver.
the driver listened carefully to einstein's lecture，which thegreat scientist gave again and again.one day he told einstein thathe knew the lecture so well that he was sure he could give ithimself.einstein smiled and said，“why don't you give the lec-ture for me next time？”the driver agreed.
that evening two of them went along to the lecture hall.nobody there had seen einstein before.as the driver took hisplace on the stage everybody clapped.then he began the lec-ture.sure enough，he did not make a single mistake.it was agreat success，and when it was over，people clapped and clapped.then he started to leave，shaking hands with everybody，whileeinstein followed quietly a few steps behind.
just before they got to the door，a man stopped them andasked the driver a very difficult question.the driver listenedcarefully.of course，he did not understand a thing，but he noddedhis head as if he did.when the man stopped talking，the driversaid that he thought the question was very interesting but reallyquite simple.in fact，in order to show how simple it was，hewould ask his driver to answer it.
一次，爱因斯坦在美国各地巡回做报告。他是坐汽车巡回旅行的，并很快就与司机非常友好了。
司机认真听了这位伟大的科学家爱因斯坦反复做的报告。一天，他告诉爱因斯坦他非常了解这个报告，而且他肯定他自己就可以做这一报告。爱因斯坦微笑着说，“那为什么你下次不替我做报告呢？”司机同意了。
那天晚上他们两人一同去了报告大厅。那里的人以前没有见过爱因斯坦。当司机代替他走上台时，所有的人都鼓起掌来。然后他开始做报告。果然，他一个错都没出。这次报告是一个巨大的成功，结束时人们一再鼓掌。然后他起身离开，和所有的人握手，而爱因斯坦则在他身后几步远的地方静悄悄地跟着。
就在他们快到门口的时候，一个人拦住他们，问了司机一个十分难的问题。司机认真听着。当然，他一点也不懂，但他点着头好象他听懂了。等那人说完，司机说他认为这个问题很有意思，但却真的很简单，实际上，为了表示它到底有多么简单，他将请他的司机来回答。