质量是物体所含的物质量,或指某种物品的优劣,我们所说的钢琴的质量,当然是指钢琴品质的优劣。与钢琴相关的有四种人群,他们对钢琴质量的认识有所不同：一是钢琴制造者,他们关心的是自己产品的声 Quality is the amount of material contained in the object, or refers to the merits of certain items, we say the quality of the piano, of course, refers to the pros and cons of piano quality. There are four groups of people related to the piano, who have different understanding of the quality of the piano: one is the piano maker, who is concerned about the sound of their own products