C Speaking of Leonardo da Vinci, you may first think of his great works of art such as Mona Lisa and The Last Supper. But, he was not only a great painter, but also a talented inventor. When he died in 1519, da Vinci left behind more than 6,000 pages filled with his thoughts, ideas and inventions. Some of them were ahead of his time. One of da Vinci’s most famous inventions was the omithopter (飞行器) . It was a human-powered flying machine. To move the wings (翅膀) up and down, the pilot had to use either his hands or feet to provide energy for the machine. * Unfortunately, da Vinci never built the ornithopter. The world would have to wait another 400 years or so for a machine that could really fly. Actually, it wasn’t until 1903 that the Wright brothers made their first successful flight. What’s more, according to some research, the first form of a tank was drawn by Leonardo da Vinci. It was an armored tank ( 装甲坦克 ) that was designed to be able to move in any direction. Like his flying machine, the armored tank was never built. It wasn’t until 400 years later, during World War I, that tanks were first used on the battlefield.