Good morning, everyone. Today we're going to look at the history of the bicycle. Now, you might think the bicycle was invented in the 19th century, and you'd be right. But its early forms were quite different. The first two-wheeled vehicle, called the 'draisine', was invented in 1817 by a German baron. It had no pedals; you pushed your feet against the ground to move. Then, in the 1860s, pedals were added to the front wheel. However, this design was unstable because the front wheel was very large. It wasn't until the 1880s that the 'safety bicycle' appeared, with a chain drive and two equal-sized wheels, making it much safer. This design quickly became popular and is the basis for modern bicycles.
❓ According to the lecture, what was the main problem with the bicycle design in the 1860s?
A. It had no brakes.
B. The front wheel was too large, making it unstable.
C. It was too heavy to ride uphill.
D. The pedals were difficult to use.
✅ 正确答案
The front wheel was too large, making it unstable.