"The King's 24 Violins" is mentioned in line 15 to illustrate（）
A. how the violin became a renowned instrument
B. the competition in the 1600's between French and Italian orchestras
C. the superiority of French violins
D. why the violin was considered the only instrument suitable to be played by royalty
腐败作用不会
A. 提供部分脂肪酸
B. 产生少量维生素
C. 直接产生假性神经递质
D. 产生NH3
The word "unprecedented" in line 25 is closest in meaning to（）
A. slow
B. profitable
C. not seen before
D. never explained
Basalt, (which )composes (most) of the ocean (floor), is a dark-grey rock (rich )in iron and magnesium than most surface rocks.（）
A. which
B. most
C. floor
D. rich
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