It is a convenient kind of transportation．It is also great exercise．And it makes a healthy lifestyle．Do you know what it is？Yes，we are talking about biking．

Most of us know that biking is a clean and cheap way to get around a city．It not only reduces traffic problems and pollution，but it is also good for people's health．

In many countries，bike﹣friendly facilities（设施） are making people's lives better．

In the world's top bike﹣friendly city，Copenhagen，the capital city od Denmark（丹麦），traffic lights in main crossings are always green for bike riders during peak（高峰） hours．And when it's snowy，the snow is cleared from the bicycle roads first and then car roads．

The US has a special day to encourage people to ride bikes．It is Bike to Work Day on May 20^th．To make cycling easy，the government had built over 200cycle roads until 2014．

In China，you can also find a few bike﹣friendly cities．Xiamen is one of them．You can rent bikes and take a ride on the circular road（环岛路）．In Xiangtan，people have been able to rent bikes in busy areas of the city in the past two years．It's very convenient and liked by many people

46．What is the text mainly about？　　．

A．Great exercise．

B．A healthy lifestyle．

C．Biking．

47．From the text，we know that the world's top bike﹣friendly city is in　　．

A．Denmark

B．America

C．China

48．May 20^th is a special day in America to encourage people to go to work　　．

A．by car

B．by nike

C．by subway

49．The US government had built over 200　　 until 2014．

A．cycle roads

B．car roads

C．main crossings

50．Biking is liked by people in Xiangtan because it is　　．

A．cool

B．convenient

C．safe．