The noun phrase pepper and salt in “His hair is pepper and salt”

The noun phrase pepper and salt in “His hair is pepper and salt” functions as an idiom（ ）in nature.
A、nominal
B、verbal
C、adverbial
D、adjectival
【正确答案】：D
【题目解析】：本题考查句式习语。习语的形式和功能并非完全雷同。比如：名词短语 pepper and salt，在 His hair is pepper and salt（他的头发黑白相间）中用作一个形容词（adjective）。因此答案是D。