有机物A和B只由C、H、O中的两种或三种元素组成，等物质的量的A和B完全燃烧时，消耗相等物质的量的氧气，则A和B的相对分子质量的差值(其中n为正整数)不可能为    (　  　)

A．0                             B．14n

C．18n                           D．44n

The olfactory regions of the nose are yellow, richly moist, and ______.

A．fully fatty substances

B．full, fatty substances

C．full of fatty substances

D．fatty substances are full