In recent years cattle breeders have increasingly used crossbreeding, in part that their steers should acquire certain characteristics and partly because crossbreeding is said to provide hybrid vigor.
In recent years cattle breeders have increasingly used crossbreeding, in part that their steers should acquire certain characteristics and partly because crossbreeding is said to provide hybrid vigor. a in part that their steers should acquire certain characteristics b in part for the acquisition of certain characteristics in their steers c partly because of their steers acquiring certain characteristics d partly because certain characteristics should be acquired by their steers e partly to acquire certain characteristics in their steers 一道OG题。先不说答案 我的问题是:AND 和什么并列? 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, is
b stationary crests and troughs although they are formed by rapidly moving air, is
c stationary crests and troughs although the air that forms them is moving rapidly, are
the first one,  artly because....and partly because .... is a good parallelism.
second one,,in addition to usage of verb(is and are),you must notice the "Although clause",which have good logical relation with "crests and troughs that remain stationary ".try to image,if no sentence before that clause,what is "although" for?