Today we're going to discuss the history of the bicycle. Invented in the early 19th century, the first bicycles had wooden frames and no pedals, requiring riders to push their feet along the ground. It wasn't until the 1860s that pedals were added to the front wheel. However, these 'penny-farthings' were dangerous due to their large front wheels. The modern safety bicycle, with two equal-sized wheels and a chain drive, emerged in the 1880s, making cycling much safer and more accessible to the general public.
❓ 19世纪60年代发明的自行车存在的一个主要问题是什么？
A. 他们的木制框架容易断裂。
B. 它们速度太慢，不实用。
C. 它们之所以危险，是因为前轮巨大。
D. 它们没有踏板，难以操控。
✅ 正确答案
They were dangerous because of their large front wheels.