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.
❓ What was a major problem with the bicycle design in the 1860s?
A. A) It had no pedals at all.
B. B) The front wheel was too small, making it unstable.
C. C) The chain drive often broke.
D. D) The two wheels were of different sizes, causing accidents.
✅ 正确答案
B) The front wheel was too small, making it unstable.