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nowadays， bikes are very popular in towns， cities as well as villages. but do you know the history of the bike? 61 fact， the bicycle has a long and interesting history. the first bicycle 62 (invent) more than two hundred years ago. early bicycles， however， did not look like today’s bikes.

the first 63 (bicycle) were called the hobby horse. they were made of wood!

people 64 (ride) them by pushing their feet along on the ground.

later， a bicycle that had pedals (踏板) and metal tires (轮胎) was invented. it was not comfortable. it was called the boneshaker. inventors kept working 65 (make) bicycles more comfortable.

next， the high wheeler was developed. it had a very big wheel in the front. this bicycle was not easy to ride， 66 the rider sat high up on it. the rider could be 67 (bad) hurt.

then bicycles began to have two wheels that were in 68 same size. more than one hundred years ago， bicycles began to have rubber tires filled with air. that was a solution for the problem of a bumpy (不平的) ride. The new tires made riding    69    (smooth) than before.

Today, people ride bikes to get exercise. Bicycling    70    (be) safer, too.