[求助]天山 4-Q31

blanchdongxue

我觉得sth is expected that....应该没什么问题，原句可变成sth that....is expected,为了避免头重脚轻，因此把that放到后面。
如这道题：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 abilityto propel aircraft anywhere in the world within two hours or help
答案为A，that从句修饰jet engine,因为太长，所以被放到了后面
所以我认为这道题不选C的主要原因是时态混用了~
这是个人的一点拙见，如有不对请指教~