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Updated at: 2018-12-04 新题 预测 机经题

In the early years of piano construction, keys were commonly made from sugar pine.
Today they are usually made of spruce or basswood. Spruce is typically used in high-quality pianos.
Black keys were traditionally made of ebony, and the white keys were covered with strips of ivory. However, since ivory-yielding species are now endangered and protected by treaty, makers use plastics almost exclusively.
Also, ivory tends to chip more easily than plastic.