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A unmanned surveillance helicopter flies over a group of spectators during a demonstration flight in Lianyungang, a coastal city in East 皇冠体育app's Jiangsu province on Sept 23, 2012.[Photo/Xinhua] |
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Staff workers make the preparation for a drone's demonstration flight in Lianyungang, a coastal city in East 皇冠体育app's Jiangsu province on Sept 23, 2012. [Photo/Xinhua] |