After more than four decades of research and development, a new type of jet engine is being tested that could eventually propel aircraft anywhere in the world within two hours or help boost cargoes into space at significantly lower costs than current methods permit.
A. tested that could eventually propel aircraft anywhere in the world within two hours or help
B. tested that could eventually have the capability of propelling aircraft anywhere in the world within two hours or to help
C. tested, eventually able to propel aircraft anywhere in the world within two hours, or helping
D. tested, and it eventually could propel aircraft anywhere in the world within two hours or helping
E. tested, and it could eventually have the capability to propel aircraft anywhere in the world within two hours or help
E[A]
嘿嘿 。。。如果是我 我就选择A
这个题目的争议的确集中在AE之间 因为通过并列关系可以很容易的排除BCD
B中or to help的to help和前面的propelling无法并列
C中or helping和前面的to propel不能并列
D中or helping和前面的propel不能并列
AE的差别在于句子的结构不一样
A选项中that实际上是后置定语从句，本身该定语从句应该在engine后面，但是由于从句过于冗长所以后置谓语后
E中将上述结构改为了并列结构，换句话说，原文说的核心意思是a new type of engine is being tested，但是E选项表达的是两个并列的意思
同时E选项中or help可以与前面的have the capability并列 也可以和后面的propel并列 不够明确
反正我选A | 
