Today's lecture is about the history of the bicycle. The first bicycle, invented in the early 19th century, had no pedals and was pushed along by the rider's feet. It was called a 'hobby horse'. Later, in the 1860s, pedals were added to the front wheel, creating the 'velocipede'. However, this design was very uncomfortable due to its rigid frame and wooden wheels. It wasn't until the 1880s that the 'safety bicycle' with a chain drive and two equal-sized wheels became popular, making cycling much safer and more accessible to the general public.
❓ Điều gì đã làm cho 'xe đạp an toàn' trở nên phổ biến hơn so với các thiết kế trước đó?
A. A. Nó có ghế ngồi thoải mái hơn.
B. B. Nó sử dụng bộ truyền động xích và các bánh xe có kích thước bằng nhau.