阅读短文，根据上下文和首字母提示，在横线上填写一个合适的单词补全短文。

Now we can see QR codes （二维码）in many places. We use the m phone to scan （扫描）QR codes. Then we can pay bills, get more information about something, add friends and so on. QR codes are u. Do you know who invented them and w he invented them?

Before QR codes were invented, people u bar codes（条形码）. A bar code can't store（储存）so much information. A Japanese man wanted to solve（解决）the problem and he invented the QR code with his team. His n  is Masahiro Hara. 
       Maybe in the future, you will find QR codes are not good enough and you may invent another kind of code. That will be great!