In today's lecture, we'll discuss the history of the bicycle. Early bicycles in the 19th century had wooden frames and iron tires, making them extremely uncomfortable on rough roads. The invention of the pneumatic tire by John Boyd Dunlop in 1888 was a turning point. It greatly improved comfort and speed, leading to a cycling boom. However, it wasn't until the 20th century that bicycles became widely affordable for the general public, thanks to mass production techniques. Interestingly, the safety bicycle, with two equal-sized wheels, emerged in the 1880s and is the design we still use today.
❓ Theo bài giảng, ưu điểm chính của lốp hơi Dunlop là gì?
A. A. Nó làm cho xe đạp trở nên rẻ hơn để sản xuất.
B. B. Nó đã cải thiện sự thoải mái và tốc độ.
C. C. Nó cho phép sử dụng khung gỗ.
D. D. Đây là thiết kế đầu tiên có hai bánh xe bằng nhau.