在CCTV的一次春节晚会上，小沈阳先模仿了阿宝的歌声，又模仿了刀郎的歌声，都惟妙惟肖，小沈阳之所以“以假乱真”，从物理声学的角度讲，声音有三个特性：____、____、____，它主要模仿了其中的____特性，才如此神似．

If your head feels very hot, you should ____ ____ ____ ．

    Jack Ma, founder of Alibaba Group, has become the richest man in China with a fortune of 150 billion yuan ($24.4 billion), according to the "Hurun Rich List 2014".

    Jack Ma was born in Hangzhou, Zhejiang Province. As a child, Mr. Ma was interested in English. He improved his English by volunteering as a tour guide. Later in his youth, he attended Hangzhou Normal University and graduated in 1988 with a bachelor's degree in English. He later became a teacher in English and International Trade at the Hangzhou Dianzi University. Then he set up his own translation company. In 1999, Mr. Ma founded Alibaba in his apartment in Hangzhou with 17 friends. He pointed out that there had never been an organization that is as large as Alibaba in the world. It welcomes about 100 million shoppers a day.

    Mr. Ma is often called China's Steve Jobs, Jeff Bezos or Bill Gates. He remains executive chairman of the company, but his decision focuses less on the blind wealth and more on improving the state of the world.