Select the sentence in the passage in which the author introduces a specific Nahuatl mode of expression that is not identified as being shared with certain European languages.
Here’s the passage. The sentence that is underlined is my answer and the sentence with the bold font is the right answer:
Whether the languages of the ancient American peoples were used for expressing abstract universal concepts can be clearly answered in the case of Nahuatl. Nahuatl, like Greek and German, is a language that allows the formation of extensive compounds. By the combination of radicals or semantic elements, single compound words can express complex conceptual relations, often of an abstract universal character.
The tlamatinime (those who know) were able to use this rich stock of abstract terms to express the nuances of their thought. They also availed themselves of other forms of expression with metaphorical meaning, some probably original, some derived from Toltec coinages. Of these forms, the most characteristic in Nahuatl is the juxtaposition of two words that, because they are synonyms, associated terms, or even contraries, complement each other to evoke one single idea. Used metaphorically, the juxtaposed terms connote specific or essential traits of the being they refer to, introducing a mode of poetry as an almost habitual form of expression.
This is the explanation given by ETS (but it’s pretty sparse in elaboration):
The passage introduces two specific Nahuatl modes of expression. One is the formation of single compound words that are capable of expressing complex conceptual relations (first paragraph); the other is the juxtaposition of two related words to evoke a single idea (second paragraph). In the formation of compounds Nahuatl is described as being “like Greek and German,” but the second mode is not identified as being shared with other languages. Therefore the sixth sentence (“Of these forms . . . one single idea”) is the best choice.
I thought the use of metaphors is Nahuatl’s second mode of expression, and my chosen sentence first introduces it. Furthermore, the “of these forms” suggests that ETS’s chosen sentence is expanding on the metaphorical mode of expression. Where did I misinterpret things here?