Today we're going to discuss the history of the bicycle. The first bicycle, invented in the early 19th century, had no pedals; riders pushed their feet against the ground. Later, in the 1860s, pedals were added to the front wheel, but this design was unstable. By the 1880s, the 'safety bicycle' with a chain drive and two equal-sized wheels became popular, making cycling safer and more accessible. Interestingly, the bicycle's popularity grew not only for leisure but also as a means of transport for workers, especially in European cities. Now, what was a key improvement of the safety bicycle?
❓ 讲座中提到的安全自行车的一个关键改进是什么？
A. A. 它的前轮上装有踏板。
B. B. 它采用了链传动和两个等大的轮子。
C. C. 它比早期型号更轻便、更快速。
D. D. 它完全不需要踏板。
✅ 正确答案
B. It used a chain drive and two equal-sized wheels.