Good morning, everyone. Today we're going to discuss the history of the bicycle. Now, many people assume that the bicycle was invented in the 19th century, and that's partly true. The first two-wheeled, pedal-less machine, called a hobby horse, appeared in 1817. However, it wasn't until 1865 that pedals were added to the front wheel, creating the 'boneshaker'. This was followed by the high-wheel bicycle in the 1870s, which had a very large front wheel. But it was the invention of the chain drive in 1885 that made bicycles safer and more practical, leading to the modern design we recognize today. So, the key point is that the development took several decades.
❓ 讲师提到的高轮自行车主要问题是什么?
A. A. 它没有踏板。
B. B. 由于其巨大的前轮,很难保持平衡。
C. C. 制造成本过高。
D. D. 它不适合长距离使用。
✅ 正确答案
B. It was difficult to balance due to its large front wheel.