Good morning, class. Today we're discussing the history of the bicycle. The first two-wheeled vehicle, called a 'draisine,' was invented in 1817 by a German baron. It had no pedals; riders pushed their feet against the ground. In the 1860s, pedals were added to the front wheel in France, creating the 'velocipede.' Later, the high-wheel bicycle became popular in the 1870s, but it was dangerous because riders sat very high. Finally, in 1885, the 'safety bicycle' was introduced with a chain drive and equal-sized wheels, making riding much safer and more practical.
❓ Vấn đề chính của xe đạp bánh cao mà giảng viên đề cập đến là gì?
A. A. Nó không có bàn đạp.
B. B. Người cưỡi ngồi rất cao, khiến việc này trở nên nguy hiểm.
C. C. Nó quá đắt để sản xuất.
D. D. Nó không thể được sử dụng trên những con đường gồ ghề.