Good morning, everyone. Today we're going to look at the history of the bicycle. Now, you might think the bicycle was invented in the 19th century, and you'd be right. But the first two-wheeled vehicle, called a 'velocipede', appeared in 1817. It had no pedals; you pushed it along with your feet. Later, in the 1860s, pedals were added to the front wheel. However, this design was unstable because the front wheel was small. It wasn't until the 1880s that the 'safety bicycle' with a chain drive and two equal-sized wheels became popular. So, the key improvement in the 1880s was...
❓ 1880년대 자전거의 주요 개선점은 무엇이었는가?
A. A. 앞바퀴에 페달을 추가하는 것
B. B. 체인 드라이브와 동일한 크기의 바퀴 도입
C. C. 페달이 없는 벨로시페드의 발명
D. D. 앞바퀴 크기의 축소
✅ 正确答案
B. The introduction of a chain drive and equal-sized wheels