提示词：智能手机 smartphone, 二维码 the QR code
I'm writing to tell you more about the new form ofsharing bike mobike mentioned in your latest letter.
It's very convenient to use if you have a smartphone. What you do is to find a nearest mobike through the APP, scan the QR code on the bike, and enjoy your trip.
Compared to other forms of sharing bike, the greatest advantage of mobike is that you can easily find one and never worry about where to park it. It is becoming a new trend as a means of transportation, which relieves the traffic pressure and does good to the environment as well.
Hope to ride a mobike with you in China.