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. Later, in the 1860s, pedals were added to the front wheel, but this design was unstable because the wheel was very large. It wasn't until the 1880s that the 'safety bicycle' with two equal-sized wheels and a chain drive became popular. This design made cycling much safer and more accessible, especially for women, who began to use bicycles as a means of independent transport.
❓ Điều gì đã làm cho xe đạp an toàn hơn và phổ biến hơn vào những năm 1880?
A. A. Việc bổ sung bàn đạp vào bánh trước
B. B. Việc giới thiệu hai bánh xe có kích thước bằng nhau và bộ truyền động xích
C. C. Việc sử dụng một bánh trước rất lớn
D. D. Việc tháo bỏ cơ chế dây xích
✅ 正确答案
B. The introduction of two equal-sized wheels and a chain drive