Researchers have explored the possibility that dolphins are able to be

This is good one

I take on 'E'.

A, B & D - 'as humans' is wrong
C - sounds as if 'humans can be trained to communicate'

OA is E.

we are comparing two actions here so as will be used instead of like.

so C is out.

only E maintains the correct comparison.
dolphins are capable of being trained to communicate as humans do(communicate)

A case of the use of proper diction and like vs as.

a) are able to be trained to communicate as humans … are able to be is not the preferred diction. Can be or could be is the right ; drop
b) were able to be trained to communicate like humans --- were able to be is still worse uses wrong tense as well as wrong diction; drop
c) can be trained to communicate like humans can …. -[color=#0000ff]Like humans can - is a clause. Like can not be used to compare clauses.
d) could be trained to communicate as humans ---- correct choice. – As - can be used to denote positions.
e) are capable of being trained to communicate as humans do --- are capable of being trained is poor diction.

A, B, D are wrong because -- When you use as it should be followed by a clause because you are making comparison here
C is wrong because -- Like cannot be followed by a clause
E is correct because -- As is followed by a clause and its a comparison

In A and D, to communicate AS HUMANS implies that the dolphins actually would BE humans when they communicate. Mary works as a doctor means that Mary actually IS a doctor.
Eliminate A and D.

In B, were trained should not be in the past tense, since the sentence is discussing an ongoing possibility: whether dolphins ARE capable of being trained.
Eliminate B.

In C, like is being used -- incorrectly -- to compare actions. LIke is used to compare nouns; AS is used to compare actions.
Eliminate C.

Hence E is the perfect answer.

Comparison can be made between two things:-
1) Dolphins, Like humans, can be trained
2) Dolphins can be trained, as humans can be.

a) are able to be trained to communicate as humans. 'Ability' is compared with 'humans'
b) were able to be trained to communicate like humans 'Ability' is compared with 'humans'
c) can be trained to communicate like humans can 'like' is used to compare actions
d) could be trained to communicate as humans Correct choice
e) are capable of being trained to communicate as humans do Use of being is generally wrong on GMAT

Dear expert GMATNinja, could you please help explain usage of "as humans" in correct answer (D)?
As far as I'm concern, [as + noun] is right only when subject of the following clause is that noun. For example,
As a teacher, Mary could assign as many exercises as she wants.
In the above example, Mary is a teacher. But in (D), how can dolphins are humans? Please shed some light. Thank you.

Besides, searching on google, I found out that in other GMAT forums, it is said that OA is (E). I wonder what actual correct answer is??
This debatable question is from Kaplan. Should I neglect further question from this source from now on? I will appreciate your advice on this.

Finally, thank you so much DmitryFarber.

So, just to be clear, here exists a similarity comparison instead of role/position comparison? Right?

Hi Daagh,

Isn't there a redundancy of possibility and could in the Option D. Kindly clarify my doubt. Thanks!

Hi mkabra123 ,

Yes, that's true. I am also doubtful about this option. Ideally possibility and could should not have come together as it leads to redundancy.

But remember our aim is always to select the best possible option. Hence, D is the best possible answer.

pulkitsharma9991, the distinction you're making isn't one I use a rule for. I think what you're asking is whether the comparison with "as" is serving to say that two things work in similar ways or to say that two things appear in similar roles/capacities. It's definitely the first. We are comparing the way that dolphins communicate with the way humans communicate. Or, more precisely, we are saying that dolphins might learn to use the same method of communication that we use. If we were comparing roles, we'd be saying that dolphins fill a similar role to ours, and there's no indication of such a role in the sentence. However, D absurdly suggests that dolphins might communicate "as humans." This would mean that dolphins were actually *being* humans. It's the same way one might say that "I act as an intermediary" or "soy milk can be used as a substitute for dairy milk." Notice that in these cases, I actually *am* an intermediary and soy milk really *is* a substitute. Dolphins are not really humans, so D is quite impossible.

DmitryFarber Agreed Sir. We are talking about similarity here. The rule I followed was when as occurs for similarities, it should occur with a verb(which isn't present in D). Hence, E. I hope my logic is right.

Ah, I see what you're saying. The way I think of the rule, "as" compares clauses, so we come to the same conclusion: the verb "do" is needed.

A B and D are completely wrong.‘as humans’ means ‘in the role of humans’ not ‘as humans communicate’, which is what the sentence wants to say.



C also changes the meaning ‘like humans can’ means ‘can be trained to communicate, in the same way humans can be trained’. Also like isn’t supposed to precede a clause.



E is the right answer.

KAPLAN OFFICIAL EXPLANATION

Read the Original Sentence Carefully, Looking for Errors:

The term “as humans” in the underlined portion indicates that the sentence may contain a comparison error. The term "as” indicates action or passage of time, but “as humans” leaves the action undefined and is erroneous. The reader could be left wondering, "as humans what? As humans can be trained? As humans can communicate?" It's not clear.

Scan and Group the Answer Choices:

A quick scan of the end of each answer choice reveals that (A), (B), and (D) contain the error noted in Step 1. (C) and (E) add a verb to the end of the “as” phrase.

Eliminate Wrong Answer Choices:

(A), (B), and (D) can be eliminated because they contain the error noted. (C) does not clarify the vague comparison. By adding the "can" at the end, the reader could still wonder, "like humans can what? Be trained? Communicate?" Eliminate (C).

(E) uses the comparison "as humans do" to make it clear that the sentence is referring to how humans communicate. "Do" could only refer to communicate. Humans do communicate. It makes no sense to say humans "do be trained." (E) is correct.

TAKEAWAY: Keep asking whether the answer choice you are examining truly provides the clarity needed.

What about ellipsis? "Researchers have explored the possibility that dolphins are able to be trained to communicate as humans [are able to be trained to communicate"]. Isn't it implied that way?

COMPARISONS


THEORY: If we use "AS" to set a comparison, we must compare CLAUSES!!


A) are able to be trained to communicate as humans ------- The word "able" implies intention, which animals don't usually have. Besides, "as humans" is wrong, since we need a verb to set the comparison.


B) were able to be trained to communicate as humans -------- Verb tense "Were" is wrong, and "as humans" needs a verb to set the comparison.


C) can be trained to communicate like humans can --------- "Like" cannot link clauses; therefore, "can" is incorrect.


D) could be trained to communicate as humans ----------- "As humans" needs a verb to set the comparison.


E) are capable of being trained to communicate as humans do ----------- CORRECT .