Your friend may also be a place where many places have similar musical instruments for free experience. In fact, it's just publicity activities, promoting sales, helping publicity and so on. And there are expert lectures to help you brainwash!

I bought one like this before, and they said that limited activities cost nearly 6000 yuan. Now the house is full of dust! My colleagues also planned to buy it, but I didn't go after reading this book because they sold it!

People who have been to give you advice, just look at it, and friends are kind. If you have any health problems, you should go to a big hospital for examination and treatment.