Good morning, everyone. Today we're going to discuss the history of the bicycle. Now, many people think the bicycle was invented in the 19th century, but actually, the first two-wheeled vehicle appeared in 1817, invented by a German baron named Karl von Drais. However, it had no pedals; riders pushed their feet against the ground to move. It wasn't until 1860s that pedals were added to the front wheel, creating the 'boneshaker'. Then in 1885, the 'safety bicycle' was introduced with a chain drive and equal-sized wheels, which became popular because it was much safer than earlier models. So, the key innovation that made cycling widely accessible was the chain drive system.
❓ Según la conferencia, ¿cuál fue la principal ventaja de la bicicleta de seguridad introducida en 1885?
A. No tenía pedales, lo que hacía más fácil montarlo.
B. Funcionaba mediante una transmisión por cadena, lo que lo hacía más seguro.
C. Tenía ruedas delanteras más grandes para mayor velocidad.
D. Era más ligero y más barato de producir.
✅ 正确答案
It was powered by a chain drive, which made it safer.