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 along the ground. This was called a 'hobby horse.' Later, in the 1860s, pedals were added to the front wheel, creating the 'velocipede.' However, it was uncomfortable due to its rigid frame. Then, in the 1880s, the 'safety bicycle' was introduced with two equal-sized wheels and a chain drive, making it much safer and more efficient. This design became the foundation for modern bicycles.
❓ 安全自行车相比早期型号的主要改进是什么？
A. A. 它的前轮上装有踏板。
B. B. 它有两个大小相同的轮子和一个链条传动装置。
C. C. 它采用了更为柔韧的框架结构。
D. D. 骑行无需耗费体力。
✅ 正确答案
B. It had two equal-sized wheels and a chain drive.