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    Recently the unmanned aircraft which are called drones (无人驾驶飞机) have come into use for a number of business purposes.

    Basically, a drone is a flying robot. The aircraft (飞行器) may be remotely controlled or can fly a{#blank#}1{#/blank#} through flight programs in their systems. The little planes used to be very costly. In the past, they were mostly used in the military (军事). But as they have d{#blank#}2{#/blank#}in price more people have begun to use them. Rescue workers and fanners are among the new users.

    A company in France is using drones to help farmers examine their crops and limit the amount of fertilizer (肥料) they use. The fast development of computer technology, image sensing devices (图像感应设备), satellite navigation (卫星导航) and cell phones has led to lower-priced drones. Researchers and developers have learned how to build smaller and less-costly drones.

    Moviemakers are using drones to film from the sky. Historians (历史学家) use them when they explore a{#blank#}3{#/blank#}. buildings. Rescue workers use them to look for people. And now farmers are using them to m{#blank#}4{#/blank#} their crops.

    Romain Faroux is a French businessman who starts companies. His father was a farmer. He believed drones could help fanners. He helped create a company that developed a small drone that could be controlled by people on the g{#blank#}5{#/blank#}. They called it “Agridrone (农业无人机).” It uses a special “optical sensor (光学感应器)” to examine crops.

    The technology used is similar to that used by smartphones except it has wings. A computer program directs the drone to fly over the crops. The sensor on the drone records four different-colored “bands” of sunlight (太阳光带) that are reflected off (反射) the crops.

    Jean-Baptiste Bruggeman is a farmer. He says the drone flies over his crops at different time of the season. He says this provides a lot of information about his crops. The drone pictures show him the exact amount of fertilizer the crops need. It also shows exactly where the fertilizer is needed.

    Romain Faroux says farmers use information g{#blank#}6{#/blank#} by the Agridrone to place fertilizer only in areas where it was needed. This saves money and reduces pollution. Before they used the drones, farmers would put the same amount of fertilizer everywhere. Drones also save time because farmers can examine u{#blank#}7{#/blank#} to three hectares (公顷) in about a minute.