only between C and D

i will go with C, superior to looks idiomatic, i may be wrong.

also D is missing the and

superior to sth. is the correct idiom here. So A,C, and E stay.

In A: "...was demonstarted [...] and being proved" is far from parallel. Moreover, as a rule of thumb, "being" is almost always wrong although that has changed a bit.

In E: "...was demonstrated [...] with [...] having been proven" is unnecessarily wordy, awkward, and complicated.

C displays the best choice. "Was demonstrated and [...] proven" is not only parallel, but also concise.

B is wrong because it does not use the correct idiom and because it uses past perfect which should only be used when it is evident that one action happened before another one did (and that is clearly not the case in this question).

IMO C.

Great explanation, jaymw, although I may suggest that you do it in a slightly different order...

>99% of you will never see the idiom "superior to" vs. "superior over" on the GMAT, so it's not really worth spending any time on. You're much more likely to swim in Lake Superior than to have to know any idioms pertaining to the word superior!

And you don't need it here. First, look at the fact that three choices use "and" and two do not. Do we need to connect "of the motorcar was demonstrated" to "its superiority"? Yes - otherwise we're just listing nouns out of context, so D is incorrect. E uses a connector so for the time being it's okay, but next let's look at verb tense, since we can see "being", "had been", etc. all used.

Because we're using parallel verbs (Once X and Y - they happen at the same time), we need to have "was", and only C uses the proper tense (which in this case is implied). A, B, and E all use incorrect verb tenses, and are therefore wrong. Only C, the correct answer, remains.

Now, it's true that C gets the idiom correct, but on the GMAT there are very few questions on which you'll have to know the idiom, so I'd look at those as "bonuses" - if you know them, great, but don't stress them if you don't. The test will reward you for systematic thinking, so focus on practicing those major errors that you know you can do well.

thanks Brian for your explanation.

My question: In option C that is correct answer by the way, doesn't it miss "was" to have good parallelism as shown in the right side ?

"was proven" it shjould be no ?

Good question, GMATMadeEasy - in C, the word "was" is implied, in the way of:

Example 1: My shirt was cleaned and ironed - the "was" in "was ironed" is implied because "My shirt" is the subject of both and "was" thus corresponds to both simultaneous actions. Hopefully this one seems pretty straightforward and correct to you.

Example 2: My shirt was ironed and my hair combed - this is more like choice C, and takes one little leap past the first example - just like both nouns correspond to "my", the "was" carries over here, too - one way to think about it is that because "was" is a "to be" verb that doesn't indicate an action but rather just a state of being, then it's not really a separate action that requires its own verb - "was" sets these qualities all in the past tense.


It's definitely "flowery" writing, but it's not incorrect. The other verbs all have definitely wrong verb tenses, so my take is that you can definitely get rid of those, and then with the remaining choice it's awkward, but the action is clearly in the past so it's not dead wrong. Often the correct answer is "awkward yet not incorrect", so you may have to use this methodology frequently - take one pass through the answer choices to eliminate definite errors, then play the remaining choices off each other to find another direct error.

One other note - that "flowery" kind of awkward writing tends to pop up a lot when the topic of the sentence is something historical, so if you have that in the back of your mind ("it's awkward, but historical writing tends to be awkward and I can't find a direct flaw so it must be okay") that can help you rationalize some awkwardness in your answer.

Thanks Brian. I had never used Ellipsis this way, so I thought it is incorrect.
I do not know source of this question , found it in a SC document .

Isn't it a bit diffcult to find this type of Ellipsis ?