there are many songs that can be used locally, and many songs are C, Am, Dm and G. In fact, F and Dm can be mixed or replaced with each other, and some songs should be C, Am, F, G and C (the original F becomes F and G and then stabilized with C).
most major songs can be applied. In the development of their world pop music, the major C, F and G (level G(145) have developed to a certain time, and people think it is more tactful to add an Am before F, and the popular music has become more lyrical today.