求助OG16Verbal分册SC第16题中关于并列的疑问

宫明哀

题目：
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
答案选E，我选的D
求问E中不定式能和后面未划线部分的从句平行吗，我在曼哈顿上没找到这种用法，如果有人知道这种用法的出处，请指出，谢谢~

Alexnemo

OG的解释是partly ... partly 平行，来解释原因，我感觉是corssbreeding发出这个acquire的动作好一点