当OG也靠不住时。绝望还是希望。一起讨论语法205

205. The peaks of a mountain range, acting like rocks in a streambed, produce ripples in the air flowing over
them; the resulting flow pattern, with crests and troughs that remain stationary although the air that forms
them is moving rapidly, are known as "standing waves."
(A) crests and troughs that remain stationary although the air that forms them is moving rapidly, are
(B) crests and troughs that remain stationary although they are formed by rapidly moving air, are
(C) crests and troughs that remain stationary although the air that forms them is moving rapidly, is
(D) stationary crests and troughs although the air that forms them is moving rapidly, are
(E) stationary crests and troughs although they are formed by rapidly moving air, is

请大家看OG关于DE比较的解释。

Answer to Question 205
The main challenge in this sentence is to observe the agreement of subject and verb (the resulting flow
pattern... is known...) despite the distraction of a complex intervening structure containing several plural
elements (with crests and troughs...). Choices A, B, and D can, therefore, be eliminated because they use an
incorrect plural verb form, are. Choice E uses the correct verb form, is, but it incorrectly introduces a dependent
adverbial although clause into a prepositional phrase (with crests ...). Choice D also makes this error. Such
dependent clauses can only occur in the predicates of full clauses. C, the best choice, uses the correct verb form,
is, and correctly puts the although clause inside the predicate of the relative clause (that... rapidly).

D. are 不对， E/C.的 is 就对了.

D/E. 在with介词短语中插入了 although从句，错误；C中将although放在that定于从句中，就可以。

说的挺清楚的啊.先从动词第三人称单数排除A,B,D.  选项E因为在介词with引导的介词短语中加有从句,所以错.只有c正确.

I think the explaination is clear.