Good morning, everyone. Today we're going to talk about the history of the bicycle. Now, many people assume that the bicycle was invented in the 19th century, and that's partly true. However, the very first two-wheeled vehicle, called a 'velocipede', appeared in France in the 1790s. It had no pedals; riders pushed their feet against the ground to move forward. Later, in the 1860s, pedals were added to the front wheel, but this design was uncomfortable and difficult to ride. It wasn't until the 1880s that the 'safety bicycle' with a chain drive and two equal-sized wheels was developed, making cycling much safer and more popular. So, the key innovation that made bicycles widely used was the chain drive system.
❓ Theo bài giảng, điều gì đã khiến xe đạp trở nên được sử dụng rộng rãi?
A. Việc bổ sung bàn đạp vào bánh trước
B. Sự phát triển của hệ thống truyền động xích
C. Phát minh ra xe đạp chạy bằng chân ở Pháp
D. Việc sử dụng hai bánh xe có kích thước bằng nhau mà không có xích.