Good morning, everyone. Today we're going to discuss the history of the bicycle. Now, many people think the bicycle was invented in the 19th century, but in fact, the first two-wheeled vehicle, called a 'velocipede', appeared in France in the 1790s. However, it had no pedals; riders pushed their feet against the ground to move forward. It wasn't until 1860s that pedals were added to the front wheel. But this design was unstable and difficult to ride. Then, in 1885, a British engineer named John Kemp Starley introduced the 'Rover Safety Bicycle', which had a chain drive to the rear wheel and equal-sized wheels. This design made riding much safer and more comfortable, and it became the basis for modern bicycles.
❓ According to the lecture, what was the main improvement of the Rover Safety Bicycle?