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


The answer is E. I remembered that the expression should be "capability of doing something" or "ability todo something". Is it correct here to use "capability to do something"? Thank you very much.

我个人觉得D是正确答案

D如果是or help我觉得就对了，or helping不对

look a the verb propel.

so the help should be help, not helping, not to help
only a and e left

take a look at a again..it lost a subject...

D中eventually的位置有问题,不应在could前吧