Good morning, everyone. Today we're going to look at the history of the bicycle. Now, many people think the bicycle was invented in the 19th century, but actually, the first two-wheeled, pedal-less machine appeared in 1817, called the 'draisine'. It was made of wood and had no pedals; you pushed your feet against the ground to move. However, it was not until the 1860s that pedals were added, creating the 'velocipede'. The real breakthrough came in 1885 when John Kemp Starley designed the 'Rover' safety bicycle, which had a chain drive and equal-sized wheels. This design made cycling much safer and more comfortable, and it quickly became popular. So, to summarize, the key improvement in 1885 was the introduction of the chain drive, which allowed the wheels to be the same size.
❓ Theo bài giảng, lợi thế chính của xe đạp an toàn Rover được giới thiệu vào năm 1885 là gì?
A. Nó có bánh xe bằng gỗ, giúp nó nhẹ hơn.
B. Nó sử dụng bộ truyền động xích, cho phép các bánh xe có kích thước bằng nhau.
C. Đây là chiếc xe đạp đầu tiên có bàn đạp.
D. Nó được vận hành bằng một động cơ nhỏ.
✅ 正确答案
It used a chain drive, allowing equal-sized wheels.