Today we're going to discuss the history of the bicycle. Although many people think of the bicycle as a relatively modern invention, its origins date back to the early 19th century. The first two-wheeled vehicle, called a 'draisine' or 'hobby horse,' was invented by Karl von Drais in 1817. It had no pedals, and riders pushed themselves along with their feet. Later, in the 1860s, pedals were added to the front wheel, creating the 'velocipede.' However, this design was uncomfortable because of its rigid frame. Then, in the 1870s, the 'penny-farthing' appeared with a large front wheel and a small rear wheel. It was faster but dangerous. Finally, the modern 'safety bicycle' with two equal-sized wheels and a chain drive was developed in the 1880s, which became the standard design we use today.
❓ Theo bài giảng, vấn đề chính của xe đạp velocipede là gì?
A. Nó không có bàn đạp, khiến việc di chuyển trở nên khó khăn.
B. Nó quá nhanh và nguy hiểm đối với người lái.
C. Khung cứng của nó khiến việc đi xe trở nên không thoải mái.
D. Nó có hai bánh xe kích thước khác nhau, gây ra sự mất ổn định.