A bicycle is a two-wheeled machine that is pedaled by the rider's feet. People A __________ bikes for hundreds of years. Historians disagree about the invention of the bicycle. Some historians think that Leonardo da Vinci B __________ a sketch of a bicycle in 1492. The first two-wheeled rider-propelled machine C __________ by Baron Karl von Drais de Sauerbrun of Germany. In 1817 he rode it for 14 km. D __________ frame was made of wood and this bike didn't have pedals. Nowadays there are different kinds of bikes. The mountain bicycle is used for riding on rough roads. It has E __________ than 10 speeds, wide tyres, and strong wheels.