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　Man has always wanted to fly．Some of the greatest men in ___1___ have thought about the problem．One of ___2___, for example, was the great Italian artist, Leonardo Vinci (达·芬奇)．In the sixteenth century he made ___3___ for machines that would fly．___4___ they were never built．Throughout history, other less famous men have wanted to ___5___．An example was a man in England 800 years ago．He made a pair of ___6___ of chicken feathers．Then he ___7___ them to his body and jumped into the ___8___ from a tall building．He did not fly very far．___9___, he fell to the ground and broke every ___10___ in his body．

　The first real steps took place in France, in 1783．Two brothers, the Montgolfiers, ___11___ a very large“hot air balloon”．They knew that ___12___ air rises．Why not fill it with it? The balloon was made ___13___ cloth and paper．In September of that year, the King and Queen of France came to ___14___ the balloon．They watched it carry the very first air ___15___ into the sky．The passengers were a sheep and a chicken．We do not know ___16___ they felt about the trip．But we ___17___ know that trip lasted eight minutes and that the animals ___18___ safely．Two months later, two men did the ___19___ thing．They rose above Paris in a balloon of the same kind．Their trip ___20___ twent-five minutes and they travelled about eight kilometers．