https://www.quora.com/What-does-notation-like-p-mf-mean-in-music
Let’s use your “p-mf” as an example.
If you happen to be in a repeated section, then it is most likely that the composer intends the first repetition to be played piano and the second mezzo forte.
The other possible interpretation is piano immediately followed by mezzo forte. There is a special marking fp, fortepiano, that is interpreted in such a manner. But in your case, such an interpretation is much less likely.
所以f ->p 就是第一遍 FORTE， 第二遍 PIANO。
休止符那个不弹。写上去是记谱标准。和后面的那个低音 C和A音符 构成完成的4拍。否则你直接看到后面的 C/A 会怀疑谱子写错了。
另外，咱们这种自学的，看到谱子后可以网上找一下别人弹的示范，免得弹错。
