原题
The earliest ancestor of the modern bicycle is probably a machine used in England in the early 1800s called a hobbyhorse. It h two whe and a pl to s, but n pedals; rid would pu it al with th feet. La, an inventor added pedals directly to the front wheel, like a modern child's tricycle. This version, with a huge front wheel, was faster, but it was unsafe. Riders were high off the ground, and the two wheels were close together, making both balance and stopping difficult.
参考答案：ad els ace it o ers sh ong eir ter
解题思路
老师暂未填写解题思路。