OG-95

cindypalau

95.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

E. stationary crests and troughs although they are formed by rapidly moving air, is

OG的解释是这样的： subordinate clause in the passive voice following “although” is awkward and unclear
我不太懂对这个语法点解释（被动语态的短语不能用although?)，E为什么错。   谢谢~

AlohaDJ

http://forum.chasedream.com/GMAT_SC/thread-575381-2-1.html

lz看这个帖子的10楼解释“QQ上问了一个NN，支持你解释

他说因为altough是连词， with是介词， with后+名词+连词引导一个分句是不正确的，而that因为引导定语从句，套在with引导的介词短语内，是可行的。

网上查了一下although的用法，因为是连词所以两边应该都有完整句子结构，除非有重合可省略部分。”

同意这个解释，although是连词，E中用了although其实成了sentence fragment.

hermanchang

我觉得这道题考查意思的还原要精准把，原句是：although the air that forms them is moving rapidly，意思为：虽然形成他们的空气移动非常快，而E中的是 although they are formed by rapidly moving air，意思为：虽然他们是由快速移动的空气形成的，两句话意思完全不同。E大大改变了原句的意思了，所以错误。

willrock123

同意，e 中although 用法改变了原文意思，面目全非经常错