Good morning, everyone. Today we'll discuss the history of the bicycle. The first two-wheeled vehicle, called the draisine, was invented in 1817 by Karl Drais. It had no pedals; riders pushed their feet against the ground. Later, in the 1860s, pedals were added to the front wheel, creating the velocipede. However, it was nicknamed the 'boneshaker' because of its rigid frame and rough ride. By the 1880s, the safety bicycle appeared with a chain drive and equal-sized wheels, making it much more stable and popular among both men and women. This design became the basis for modern bicycles.
❓ 安全自行车相比早期型号的主要改进是什么？
A. A. 它有一个带踏板的前轮。
B. B. 它采用了链传动和等大的车轮，使其更加稳定。
C. C. 它更轻便，生产成本也更低。
D. D. 它装有橡胶轮胎，行驶起来更平稳。
✅ 正确答案
B. It used a chain drive and equal-sized wheels, making it more stable.