og 12 蓝本 SC 24 跪求解答！！

WALLMAGE

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.
画线部分是：in part that...characteristics
D partly because certain characterisitcs should be acquired by their steers
E partly to aquire certain characteristics in their steers
答案：E
我选的答案是D，因为明明就是说原文中有语气词的不能随意更改或删除么，所以E选项中没有should就应该是错的。。。
求大家解答啊！！

hjbb1027

我觉得
从结构平行上看，D选项最好，但是，从整个句子上，它提供了一个新的题点：
“并列的成分用来表明1、the goal of doing so ;&2、 the reason for doing so ”
我也是从句子结构平行上选了D，感觉跟should的使用没什么关系。

“Here we are learning two things about the use of crossbreeding: the goal of doing so (to acquire certain characteristics) and the reason for doing so (because it provides vigor). We have to mis-match to convey the correct meaning。”

AnttiZhang

我也纠结与D和E之间，但不是因为should.

larrylw

我来试着解答一下 根据Manhattan的解释，在GMAT考试里，

should表示"moral obligation"而不是"likelihood"。来看一个例子：
The court ruled that the plaintiff must pay full damagaes.

(Correct)
The court ruled that the plaintiff should pay full damages.

(Incorrect. The word "should" means "moral obligation" -

something that a court cannot impose)
回过来看题目，题目是用两个并列的分句说明crossbreeding增加的

原因，acquire certain characteristics是crossbreeding可能获得

(likelihood)的一个优势，和"moral obligation"无关，因此不能用

should，排除D。