In the sentences such as mentioned above "to do so" is almost always correct than "to do it". May be you can remember this rule.

Q.Although it is conceivable that certain electronic devices implanted in the brain may some day correct blindness ...... there is now no clear evidence...
We need a 'that' at the end of evidence to introduce the clause that will follow, leaving us with c and d. C is correct

looking at b. Although it is conceivable that certain electronic devices implanted in the brain may some day correct blindness... there is now no clear evidence of their doing that
by adding 'doing' we are changing the tense and the meaning. The sentence means to say that there is no evidence that X can cure Y. Answer B says that there is no evidence that they are curing y right now. (it is also a bit wordy)

hope that is clear.

From my memory, I think after ‘evidence’ there should be ‘that S+V’
Thus, a, b and e are wrong.
Between C and D, it can not refer back to the electronic devices may correct blindness.
Thus it is C


Please next time, do not show the answer. Thanks.

Can somoone help me identify subject in this sentence.

Although "it is" - What should it point to?
In answer choice - " that they" - What does they point to - electronic device?

In such instances, in which it is difficult to spot the subject and the rest of the stuff, we should flip the sentence or in other words, re-write the sentence in the normal fashion. As such we can re-write the given sentence as below.


That certain electronic devices implanted in the brain may someday correct blindness caused by nerve damage is conceivable, although there is now no clear evidence of their ability to do it.

Now the subject and verb will unfold. The entire phrase starting with -That certain electronic devices implanted in the brain may someday correct blindness caused by nerve damage – is the subject while the verb is the word – is –

Now you may see that in although it is, it should point to the subject that I mentioned above.

“That they"- they in this case stands for certain electronic devices. , as you have rightly pointed out.
_________________

At present we have no evidence of life on other planets.
vs
Do you have evidence that this treatment works?

both EVIDENCE OF & EVIDENCE THAT are idiomatic but their usage differ!
hope this helps :D

The problem in D is not the conjunction that, but the pronoun it. What does it stand for? Logically it should stand for the correction of the blindness but there is no such explicit antecedence in the sentence. May some day correct blindness is a verbal phrase and can not be replaced by a pronoun. Hence D is wrong. To do so rather brings out the intent explicitly
_________________

C. but not sure why others are wrong. i chose it coz it "sounded" right. pkit can u explain plz?
_________________

Lets wait for others to respond, and then I will provide my explanations.
_________________

Convinced that we need to have a subject pronoun such as 'they' to represent the electronic devices rather than the possessive and adjective ‘their’, we can narrow down to choices C and D. In D however, the pronoun ‘it’ can not justifiably and logically stand for blindness. Hence C is the choice
_________________

I will go for C.

(a) is wrong because the use of "it" is incorrect, as "it" is a pronoun which can only tie back to noun but not Verb. Hence (A) is wrong.
Secondly use of "of their ability" is ambiguous and awkward.
And in answer (C) this mistake has been eradicated.

One more C.

Although it is conceivable that certain electronic devices implanted in the brain may someday correct blindness caused by nerve damage, there is now no clear evidence of their ability to do it.

A of their ability to do it
B of their doing that
C that they can do so
D that they might one day be able to do it
E to do so

Hi,

There is a "it" in starting of the sentence, second "it" will point to whatever first it is pointing to i.e. "correction of blindness." and I dont feel D is wordy and I feel its the better answer .. Please someone chime in

Here is the question:

Although it is conceivable that certain electronic devices implanted in the brain may someday correct blindness caused by nerve damage, there is now no clear evidence of their ability to do it.
a) of their ability to do it
b) of their doing that
c) that they can do so
d) that they might one day be able to do it
e) to do so

Hi Sausha80, Thanks a lot for your question.
However, I suggest you make use of a spoiler in the future for comments such as this I selected (b) but it seems the correct answer is (c). Can somebody please help me understand why (c) is correct and why others are wrong?, or you can also try and posting in it in a different reply.

Doing so will allow people to get a better training for the exam
Thanks
Cheers
J

KAPLAN OFFICIAL EXPLANATION:

C.

On a question as short as this, you don’t have to worry as much about scanning for differences. Just read quickly through the answer choices and you should be able to “hear” which one’s best. In (C), “doing so” is an academic sounding but correct usage which can pop up on the GMAT.Watch out for it and other bookish-sounding phrases typical of GMAT style. If you can’t use your ear for correct English, use logic and process of elimination. (E) is short. That might be a reason to prefer it. But if you plug (E) in, you see it makes the sentence say that “evidence” is doing something. In (A) , (B) and (D),“it” and “that” are ambiguous. That is, they don’t clearly refer to one and only one noun.
_________________

Hello from the GMAT Club VerbalBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________