How many volts of electricity can an electric eel emit?
【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?()