D - The diet was largely vegetarian, meat a rarity. - 对于D的解释,OG写道"because it lacks a function word such as with to link it to the main clause" 可以看出 ETS似乎并不认可n.+n. 这样的独立主格形式
E - The diet was largely vegetarian, with meat as a rarity. with复合结构(with+n.+介词短语)独立主格(前辈们说这是表紧密关系),作伴随状语修饰前面的句子。