In today's lecture, we'll discuss the history of the bicycle. The first two-wheeled vehicle, called a draisine, was invented in 1817 by Karl von Drais. It had no pedals; riders pushed their feet against the ground. Later, in the 1860s, pedals were added to the front wheel, creating the velocipede. However, this design was uncomfortable due to its rigid frame. By the 1880s, the safety bicycle emerged with a chain drive and equal-sized wheels, making it much safer and more practical. This design became the basis for modern bicycles.
❓ Điểm cải tiến quan trọng của xe đạp an toàn so với các thiết kế trước đó là gì?
A. A) Nó có bánh trước lớn hơn
B. B) Nó sử dụng bộ truyền động xích và các bánh xe có kích thước bằng nhau