A、Acute hearing. B、A music degree. C、The talent for music. D、The ability to forecast sales. A

It is one of the oldest and most complicated musical instruments. Business partners Bruce Fowkes and Ralph Richards have been building them for decades.
    “When I was a kid, one of my teachers let me go inside of one of the organs, and I was just struck by all the mechanism and it’s so fascinating.” But to be a good organ-maker, Richards says you need a perfect ear, an engineering degree and the talent for craftsmanship, and that for salesmanship that helps, too. “The first thing we do is we meet with a client.” Afterwards, they’ll inspect the space where the future organ will be installed and then design it with the help of specialized software. The rest is done by old-fashioned way—by hand.
    “This is the casting. What we do is we take some tin and lead, put them in the pot, melt them in here to 800 degrees. We ladle the metal into this pot.” The hot molten metal has been poured onto a table to form a thin sheet that will then be cut and shaped into pipes. More tin makes the sound richer. More lead, duller. After the pipes are made, Bruce manually tunes each one in a process called voicing.
    “If I want more volume, I would open this tone. If I want to be quieter, I might close the tone.” Every little thing matters when building such a complex instrument, even the way certain types of wood react in different weather. So making even a small perfect sounding organ can be a long and difficult task, let alone building one for a cathedral.
    “Small organ can have less than 1000 pipes in it and a cathedral organ might have 10,000 pipes in it.” Building an organ can take up to a year, testing it a few more months, so even though Ralph and Bruce have been in business for decades, they have only made 24 of these musical instruments. The price to build each one can run as high as a million dollars, but all it takes is to hear the tones from a perfectly tuned and perfectly built pipe organ. To know, it was worth every penny.
    Question 19. What does it take to be a good organ-maker according to Richards?
    Question 20. What process is Bruce responsible for?
    Question 21. What does the speaker say about the making of an organ?