5、Man has always wanted to fly. Even as long as eight hundred years ago, an Englishman had tried. He made a pair of _ _ 21 _ _ from chicken feathers and fixed them to his shoulders. Then he jumped from a tall building. As you can imagine, he did not fly very far. _ _ 22 _ _ , he fell to the ground and broke several bones. The first real attempt at flying took place in France in 1783. The two Mongolian brothers knew that hot air rose. If they could fill a large balloon with hot air, they thought it would rise into the air and _ _ 23 _ _ . They were right. They made a very large hot air balloon of cloth and paper. It measured ten meters in diameter. They filled it with hot air and the balloon got two hundred meters into the air. It fell to earth about three kilometers _ _ 24 _ _ .
At the next attempt, they arranged for a balloon to carry passengers. We do not know what the passengers felt about the trip as they were a cock, a duck, and a sheep. But we _ _ 25 _ _ know that the trip lasted eight minutes and the animals landed safely.