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Sand is loose fragments of rock and minerals, with principal its
A B C
component being quartz.
D
Principal its should be its principal, as the possessive pronoun should precede the noun. The correct sentence should read: "Sand is loose fragments of rock and minerals, with its principal component being quartz."
原题及解答如上，但(B)rock是可数名词，不需表达单复数吗? | 
