Today we're going to discuss the history of the bicycle. Although many people attribute its invention to the 19th century, the first two-wheeled vehicle appeared in 1817, invented by Karl Drais. It was called a 'running machine' because riders pushed their feet against the ground. Later, in the 1860s, pedals were added to the front wheel, leading to the penny-farthing. However, this design was unsafe due to its high center of gravity. The modern safety bicycle, with two equal-sized wheels and a chain drive, emerged in the 1880s and became widely popular, especially among women who gained new mobility.
❓ Vấn đề lớn của xe đạp penny-farthing là gì?
A. A. Nó không có bàn đạp.
B. B. Nó quá chậm.
C. C. Nó rất nguy hiểm vì trọng tâm cao.
D. D. Nó quá đắt để sản xuất.
✅ 正确答案
C. It was dangerous because of its high center of gravity.