【答案解析】[听力原文]
Piano
The ancestry of the piano can {{U}}be traced to{{/U}} the early keyboard instruments of the fifteenth and sixteenth centuries{{U}}—{{/U}}the spinet, the dulcimer, and the virginal. In the seventeenth century, the organ, the clavichord, and the harpsichord became the chief {{U}}instruments{{/U}} of the keyboard group, a {{U}}supremacy{{/U}} they maintained until the piano {{U}}supplanted{{/U}} them at the end of the eighteenth century. The {{U}}clavichord's{{/U}} tone was metallic and never powerful; nevertheless{{U}},{{/U}} because of the variety of tone possible to it, many composers found the clavichord a sympathetic instrument for intimate chamber music. The {{U}}harpsichord{{/U}} with its bright, vigorous {{U}}tone{{/U}} was the favorite instrument for supporting the {{U}}bass{{/U}} of the small {{U}}orchestra{{/U}} of the period and for {{U}}concert{{/U}} use, but the character of the tone could not be varied save by mechanical or structural devices. The piano was {{U}}perfected{{/U}} in the early eighteenth century by a harpsichord maker in Italy, though musicologists pointed out several previous instances of the instrument.