填空题
[听力原文] 11-15
(11) In the 1870s, people began to ride a new kind of bike called the Ordinary． The Ordinary，however，was an unusual bike．(12) For one thing its wheelswere of different sizes．(13) The front wheel was fourto five feet high，while the back wheel was about a footand a half high．Because its front wheel was so large,(14) the new bike was faster and quieter．What ismore，the rider’s body was not bumped around as muchon the Ordinary．But the Ordinary wasn’t comfortablefor anyone．(15) It was so high that getting on and offwas very difficult. As years passed，other ways ofmaking a fast, light bicycle were discovered．And bythe end of the 1900s, the Ordinary was just about gone．