《打电话》这篇课文是一段惹人发笑、发人深省的相声。它描述了这样一个场景：一个年轻人在公用____打电话。本来是一件____的事情，却____聊了老半天，浪费了____时间。相声采用____的手法，对那些____观念不强、____连篇、缺乏____的人给予了辛辣绝妙的____。

如图，将矩形ABCD沿EF折叠，使顶点C恰好落在AB边的中点C′上，点D落在D′处，C′D′交AE于点M．若AB=6，BC=9，则AM的长为　____ ．

    James Dyson is a famous British inventor. One of his well­known inventions is the bagless vacuum cleaner (真空吸尘器).He 1 it in 1978. Today Dyson still2that day. “...I was the only man in the world with a bagless vacuum cleaner！” he said.

    Dyson, 65, wasn't a(n) 3at first.When he studied art at the Royal College of Art in London, he began to show an interest in design. There he invented his first product, the Sea Truck. It was a boat for4anything between islands.

    Then he started his first company to make and sell5invention. The Ballbarrow is a kind of vehicle (交通工具).But later Dyson left his6He didn't agree with his partners.

    After that Dyson began to improve on the vacuum cleaner. In 1985, Dyson took his product to Japan and7the Japanese to sell it. However, he didn't make much money. Several years later Dyson decided to8and sell the machine himself. By 2005, Dyson controlled both the European and American 9.

    Along the way, Dyson discovered the secret of10 “People will buy products if they're better”.

万里长城是古代劳动人民智慧、创造力的象征，是世界奇迹，它始建于秦，明代达到完善地步。请说出明代万里长城的东、西起止点（    ）