OG12-95 OG-95:The peaks of a mountain range, acting like rocks ina streamed,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 know as "standing waves"
(C).crests and troughs that remain stationary although the air that forms them is moving rapidly,is
(E).stationary crests and troughs although they are formed by rapidly moving air,is
选出选项没问题了,版主大人解释的很清楚,但我至今困惑的是C选项的them, 这个代词实在宾语位置的吧??怎么可以带独主的主语creats and troughs呢??各位帮忙,谢谢啦