Good morning, class. Today we're going to discuss the history of the bicycle. The first bicycle, invented in the early 19th century, had no pedals; riders pushed their feet against the ground. It was called a 'hobby horse'. Later, in the 1860s, pedals were added to the front wheel, creating the 'penny-farthing'. However, these were dangerous because riders sat high above the ground. Finally, in the 1880s, the 'safety bicycle' was introduced with a chain drive and equal-sized wheels, making it much safer and more popular.
❓ Điều gì đã làm cho 'xe đạp an toàn' an toàn hơn so với các mẫu xe trước đó?
A. Nó không có bàn đạp.
B. Nó có bộ truyền động xích và các bánh xe có kích thước bằng nhau.