Which of the following is true of the fossil deposits discussed in the passage?_____
【单选】
What does the passage mainly discuss?()
Which of the following instruments was widely used before the seventeenth century?()
The word"supplanted"in paragraph 2 is closest in meaning to()
According to the passage, what deficiency did the harpsichord have?()
According to the information in the third paragraph, which of the following improvements made it possible to lengthen the tone produced by the piano?()