Good morning, everyone. Today, we're going to discuss the history of the bicycle. As you know, the first bicycle, called the 'draisine', was invented in 1817 by a German baron. It had no pedals; riders pushed their feet against the ground. Then, in the 1860s, pedals were added to the front wheel, creating the 'velocipede'. However, this design was uncomfortable because of its rigid frame and iron wheels. It wasn't until 1885 that the 'safety bicycle' was introduced, featuring a chain drive and two equal-sized wheels, which made cycling much safer and more popular. So, the key innovation of the safety bicycle was...
❓ 강의에서 언급된 안전 자전거의 주요 개선점은 무엇이었나요?
A. 앞바퀴에 페달을 추가했다.
B. 그것은 같은 크기의 바퀴 두 개와 체인 구동 장치를 갖추고 있었다.
C. 더 가벼운 재료로 만들어졌다.
D. 좌석이 더 편안했습니다.
✅ 正确答案
It had two wheels of equal size and a chain drive.