Good morning, everyone. Today we're going to discuss the history of the bicycle. The first pedal-powered bicycle was invented in the 1860s, but it had a major flaw: the pedals were attached directly to the front wheel, making it difficult to steer. In the 1870s, the 'penny-farthing' became popular, but its large front wheel made it unstable. It wasn't until the 1880s that the 'safety bicycle' with a chain drive and equal-sized wheels was introduced, which is similar to modern bicycles. This design greatly improved stability and safety, leading to a cycling boom in the 1890s.
❓ 根据讲座内容，第一辆脚踏动力自行车的主要问题是什么？
A. A. 它没有刹车。
B. B. 踏板安装在前轮上，导致转向困难。
C. C. 它太重了。
D. D. 它的链条传动经常断裂。
✅ 正确答案
B. The pedals were attached to the front wheel, causing steering difficulties.