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| exactly，disappeared，hundreds，example，protect，when，longest，of，symbol，wide，northwest，build |
The Great Wall of China is one of the greatest wonders of the world．With a history of more than 2，000years，some parts of the Great Wall have （41）disappeared．It is，however，still a very popular place of interest．
It is the （42）longest wall ever built．It's from Shanhaiguan on the east coast to Gansu Province in the （43）northwest of China．It is about 8meters high．The top is 8meters （44）wide and it gets even wider towards the bottom where it is 15meters．It is made （45）of stone and brick．The top is hard enough for men on horseback to ride on．The wall was built by hand and it took （46）hundreds of years to finish．
No one knows （47）exactly when the building of the Great Wall was started．It is believed that the wall was built to （48）protect parts of the country during the Zhou Dynasty．Emperor Qin Shihuang joined the separate walls built by the Qin，Yan and Zhao Kingdoms．The wall was not only for protection in the north，it was also a （49）symbol of China's ancient civilization （文明）．
Today，many of the visitors go to see the wall．（50）Whenthey stand on top of a tower and look down on this wall，they can't help （禁不�。� saying"Wow，that's fantastic!"
