In the 1870s，people began to ride a new kind of bike called the Ordinary.The Ordinary，however，was an unusual bike.For one thing its wheels were of different sizes.The front wheel was four to five feet high，while the back wheel was about a foot and a half high.Because its front wheel was so large，the new bike was faster and quieter.What's more，the rider's body was not bumped around as much as on the Ordinary.But the Ordinary wasn't comfortable for anyone.It was so high that getting on and off was very difficult.As years passed，other ways of making a fast，light bicycle were discovered.And by the end of the 1900s，the Ordinary was just about gone.

Questions 16 to 20 are based on the passage you've just heard.

16.When did people begin riding a new kind of bike？

17.Why was the bike unusual？

18.How high was its front wheel？

19.What's the advantage of the bike？

20.What is the disadvantage of the bike？

【答案】

16.In the 1870s　17.different sizes

18.four to five　19.faster and quieter

20.on and off