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


OA is A. WHY?? tested following that?

you've just learned a new thing - the gmat sometimes places 'that' modifiers after the verb. i'm with you on thinking that this is rather awkward, BUT imagine the way the sentence would look if you placed the 'that'-modifier in its usual place:
a new type of jet engine 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 is being tested.
i dare you to understand what that sentence means without reading it 3-4 times - there is approximately six miles of text between 'a new type of jet engine' and 'is being tested'. so apparently, the gmat follows the rule that a modifier that doesn't contain any punctuation can't be allowed to place too much distance between a subject and its verb. notice the distinction: if you have a 'which' modifier, which is preceded and followed by commas, then that modifier can be inserted between the subject and verb even if it's miles long (because the commas elucidate the structure, thereby preventing the obfuscation shown above).

--

here are some major problems with the other answers (not meant to be an exhaustive list)
(b) bad parallelism: have the capability vs. to help
(c) bad parallelism: able to propel vs. helping; also, the hypothetical ('could') has been lost completely
(d) bad parallelism again; also, 'and' is an inappropriate conjunction (makes it seem as though two unrelated, or distantly related, things are being discussed)
(e) ridiculously wordy; same problem with 'it' as in (d)

The OA according to SET i have is E not A.

My question is why E would be correct since the answer choice has IT without clearly referring to test or new type of jet engine or four decades or research..
or May be I am understanding it incorrectly..

ok people. are we sure that this is actually a genuine, official gmatprep verbal question?

this problem should not be posted in this folder unless it's actually from the gmatprep software.
* if it's from another source, please provide an attribution, and i'll move the thread into the appropriate folder.
* if it's really from gmatprep, then please (one of the posters on this thread) post a screen shot of the problem, with the official answer. there is no reason why gmatprep problems should have multiple oa's.

thank you.

Thank you, Ron, members.

you said "and it" is wrong because it seems there are two things. I quite agree. But, in OG book, "and it" is said to create "run-on" sentence. Pls, explain run-on sentence. Thanks.

a run-on sentence is a construction in which 2 separate sentences (independent clauses) are just stuck together, either by a comma or by nothing at all (just glued to each other).

for instance:
you can go now; i'm home --> not a run-on; a semicolon has the same function as a period.
you can go now, i'm home --> run-on
you can go now i'm home --> run-on

the OG also explains the concept of "run-on sentence" on page 653 of the text.

--

in any case, i believe that you are misquoting the OG, as it's impossible to create a run-on sentence with "and". (in fact, the use of constructions such as "and" is a common way of avoiding run-on sentences.)

if the OG really does make the claim you're saying it makes, then please give a specific page reference or problem number. thanks.