In today's lecture, we'll discuss the history of the bicycle. The first two-wheeled vehicle, called the draisine, was invented in Germany in 1817. It had no pedals; riders pushed their feet against the ground to move. Later, in the 1860s, French inventors added pedals to the front wheel, creating the velocipede. However, this design was uncomfortable due to its rigid frame and wooden wheels. It wasn't until the 1880s that the modern safety bicycle, with a chain drive and equal-sized wheels, became popular, making cycling safer and more accessible for everyone.
❓ 根据讲座内容，脚踏车的一个关键问题是什么？
A. 它太重了，无法骑上坡。
B. 它没有刹车。
C. 其车身框架僵硬，车轮为木质，导致乘坐不适。
D. 对大多数人来说，它太昂贵了。
✅ 正确答案
Its frame was rigid and wheels were wooden, causing discomfort.