托福 考试写作之历年托福考生优秀范文24
Piano
The ancestry of the piano can be traced to the early keyboard instruments of the fifteenth and sixteenth centuries --- the spinet， the dulcimer， and the virginal. In the seventeenth century the organ， the clavichord， and the harpsichord became the chief instruments of the keyboard group， a supremacy they maintained until the piano supplanted them at the end of the eighteenth c
