帮帮忙
參考答案:A piano or pianoforte is a musical instrument classified as a keyboard, percussion, or string instrument, depending on the system of classification used. The piano produces sound by striking steel strings with felt hammers that immediately rebound allowing the string to continue vibrating. These vibrations are transmitted through the bridges to the soundboard, which amplifies them.
The piano is widely used in western music for solo performance, chamber music, and accompaniment. It is also very popular as an aid to composing and rehearsal. Although not portable, and often expensive, the piano's versatility and ubiquity has made it among the most familiar of musical instruments.
The word piano is a shortened form of the word pianoforte, which is seldom used except in formal language and derived from the original Italian name for the instrument, gravicèmbalo col piano e forte (literally harpsichord with soft and loud). This refers to the ability of the piano to produce notes at different volumes depending on how fast its keys are depressed.