first --
OFFICIALLY CORRECT ANSWERS ARE CORRECT!
do not question officially correct answers!
far too many students on this forum make the mistake of questioning the correct answers; please note that doing so is a complete waste of your time and effort. i.e., exactly 0% of the time that you spend posting "isn't this official answer wrong?" is productive, and exactly 100% of that time is wasted.

"is this correct?" is NEVER a productive question to ask about one of GMAC's correct answers -- the answer is always yes.
"is this wrong?" / "is this X type of error?" is NEVER a productive question to ask about one of GMAC's correct answers -- the answer is always no.

instead, the questions you should be asking about correct official answers, if you don't understand them, are:
"why is this correct?"
"how does this work?"
"what understanding am i lacking that i need to understand this choice?"

this is a small, but hugely significant, change to your way of thinking -- you will suddenly find it much easier to understand the format, style, and conventions of the official problems if you dispose of the idea that they might be wrong.

--

in response to your question --
if you think that this is a run-on sentence, then you are probably just looking at the underlined parts and not at the way they fit into the original prompt.
if you look back at the original prompt, you'll notice that the first clause is preceded by “before”, which in this instance is serving as the required conjunction.

Ron,
I am bit confused...Below is a similar SC from MGMT .New subject company's manager has been introduced.Can you please let me know why do we need to introduce a new subject?

By applying optimization techniques commonly used to plan operations, it is possible to determine how much effort ought to be devoted to each of a company’s products in order to meet its goals in both the short and long terms.

A.it is possible to determine how much effort ought to be devoted to each of a company’s products in order to meet its goals in both the short and long terms

B.a company’s managers can determine how much effort should be dedicated to each of the company’s products in order to meet its short and long term goals

C.it can be determined by company managers how much effort ought to be devoted to each of the company’s products in order to meet its goals, both short and long term

D.it may be possible for company managers to determine how much effort should be dedicated to each of these products in order to meet the company’s short and long term goals

E.managers at a company can determine how much effort ought to be dedicated to each of these products in order to meet the company’s goals in both the short and long term

oa is b

ganile,
Look at what is going on what that opening modifying phrase. "By applying optimization techniques commonly used to plan operations," . . . . should be followed by WHO is going to be applying the techniques. The sentence as written currently is a dangling modifier; it is describing a person or people, but these people does not actually appear in the sentence. B corrects this error by putting the people right after the comma.

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Jamie Nelson
ManhattanGMAT Instructor

I have a question about C (correct answer).
I don’t really understand why they use “past simple, past simple” structure in this choice.
I mean since we have one past event and another past event that happened earlier, I thought we should use “past simple, past perfect “structure here, i.e.:

Before scientists learned how to synthesize the growth hormone, it had had to be painstakingly removed in small amounts from the pituitary glands of human cadavers.

Though, I admit that it sounds very awkward. Still, the earlier action is obviously had an impact (bearing) on the later event (scientists synthesized synthetic hormone exactly because the natural one was hard to get).
So, can experts explain why GMAT people don’t use past perfect for the second part of the sentence?
Thanks

the sentence can be viewed as a simple sequence of two past events; in such sequences, the verbs are generally both in the simple past tense unless the *former* had a direct bearing on the *latter*.



not really. the relationship is more the other way around; the latter event had a discernible impact on the former situation, but the inverse is not necessarily true. (we don't know that the difficulty of acquiring the hormone spurred the development of synthetic production; perhaps that development was accelerated by something else, such as cost savings.)

--

in general, if you see "before" or "after" in a sequence of two past events, the default is for both events to appear in the simple past tense.

sorry for reopening this thread - but couldnt help but notice that this would be a perfect modifier if not for the words " make a synthetic hormone", since synthetic already means man-made (so its redundant).

Either way, if option C read like this, would it be correct?


Before learning how to synthesize a growth hormone, scientists had to remove it painstakingly in small amounts from the pituitary glands of human cadevers.

I would assume the above is right since scientists rightly modifies the preceding phrase?

Do let me know if i'm wrong in my thinking
Thanks!

your version looks fine.

just for your information, you've used the word "modify" backward -- you're saying that "scientists" modifies the thing that is actually the modifier. that's the wrong way: the modifier modifies "scientists".

The correct answer choice is - scientist learned how to synthesize the growth hormone, it had to be painstakingly removed

Here, the antecedent of 'it' is 'growth hormone'. Isn't 'growth hormone' placed very close to 'it' for it to be the antecedent of 'it'?

Could somebody help me understand please? I have my exam in 5 days

there are no restrictions on the distance between a pronoun and its antecedent.

Hi Ron ,
Just a question about the above . Is the above always true ? can you provide some example for this

As Ron said, this is true "in general", which means not necessarily always true..

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Tim Sanders
Manhattan GMAT Instructor

Ron, Manhantan experts, pls, comment my following idea

It is easy to understand that D is wrong because "it" illogically refers to "synthetic hormone" but it is hard to realize the error.

How do we do with this problem? how do we do with this situation, in which there is an easy-to-understand but hard-to-find error

Well, I am a big believer in *always* checking out any pronouns you see, because pronouns are so commonly used to create answer choices.

The most commonly incorrectly used pronouns are it, its, they, them, and their. We call them "the deadly five". When you see these pronouns in answer choices, definitely check to see if they are used correctly. The majority of the time they will be wrong.

I hope that this helps!

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Jamie Nelson
ManhattanGMAT Instructor

Before learning how to synthesize a growth hormone, scientists had to remove it painstakingly in small amounts from the pituitary glands of human cadevers

I have a question about option d:

I understand that there is an issue with It and it refers to synthetic growth hormone and that doesnt make sense in the sentence.

Can we also say that "Before learning...hormone" is a modifier and when we are showing two events in past tense, its better to show the former event in past/ past perfect tense. And "before learning" also means that action didnot complete in the past.

Please advice!