Good morning, everyone. Today we're going to discuss the history of the bicycle. Now, most people think the bicycle was invented in the 19th century, but its origins actually go back much further. In fact, a primitive two-wheeled device, called a 'celerifere', appeared in France around 1790. It had no pedals, and riders pushed themselves along with their feet. Later, in 1817, a German inventor added a steering mechanism, making it easier to turn. However, it wasn't until the 1860s that pedals were attached to the front wheel, creating what we now recognize as a bicycle. So, to summarize, the key development that made bicycles practical was the addition of pedals.
❓ Theo bài giảng, sự phát triển quan trọng nhất để làm cho xe đạp trở nên thực dụng là gì?