Good morning, everyone. Today we're going to discuss the history of the bicycle. Now, you might think the bicycle was invented in the 19th century, and you'd be right. However, the first two-wheeled vehicle, called a 'draisine', appeared in 1817. It had no pedals; riders pushed their feet against the ground to move. Then, in the 1860s, pedals were added to the front wheel. But this design was unstable because the front wheel was small. It wasn't until 1885 that the 'safety bicycle' was introduced, with a chain drive and two equal-sized wheels, which made riding much safer and more efficient.
❓ 19世纪60年代的自行车设计存在什么主要问题?
A. 它完全没有踏板。
B. B) 前轮太小,导致不稳定。
C. C) 链条传动经常断裂。
D. D) 两个轮子大小不一,导致事故发生。
✅ 正确答案
B) The front wheel was too small, making it unstable.