I think you are kind of confused on several aspects so let me solve this question again:

Fossils of the arm of a sloth found in Puerto Rico in 1991, and dated at 34 million years old, made it the earliest known mammal of the Greater Antilles islands.

(A) sloth found in Puerto Rico in 1991, and dated at 34 million years old, made it the earliest known mammal of

>> Remove the modifiers and see what is left: "Fossils of the arm of a sloth..made it the earliest known mammal..." - reject

(B) sloth, that they found in Puerto Rico in 1991, has been dated at 34 million years old, thus making it the earliest mammal known on

>> Remove the modifiers and see what is left: "Fossils of the arm of a sloth..has been dated at 34mn years..." - is fine so keep it.

(C) sloth that was found in Puerto Rico in 1991, was dated at 34 million years old, making this the earliest known mammal of

>> Remove the modifiers and see what is left: "Fossils of the arm of a sloth..was dated at 34mn years..." - is fine so keep it

(D) sloth, found in Puerto Rico in 1991, have been dated at 34 million years old, making the sloth the earliest known mammal on

>> Remove the modifiers and see what is left: "Fossils of the arm of a sloth..have been dated at 34mn years"

(E) sloth which, found in Puerto Rico in 1991, was dated at 34 million years old, made the sloth the earliest known mammal of

>> Remove the modifiers and see what is left: "Fossils of the arm of a sloth..was dated at 34mn years"

Second question to ask: is there SVA? For that we need to ask what is being dated? The sloth or the fossils? It has to be the latter so we can:

Eliminate B,C,E

Now let us compare A and D:

Were the fossils the oldest living mammal or the sloth? It is the sloth - so whenever you see 2 answer options where one of them replaces the pronoun with the right noun - there is a very good chance you are looking at pronoun ambiguity.

Therefore, D

Now I did not even use modifiers because in such questions it can get very confusing. Again, there are other errors but I am just showing you a simple way to get to the answer.

Here are some general rules:

A large section of the employees now have the choice to work from home -> WRONG


A large section of the employees now have the choice to work from home -> CORRECT

This is because in a prepositional phrase it will always be the subject of the phrase that decides the verb.

A box of toffees was kept on the table -> CORRECT

Now, let us see how it changes when we. use modifiers:

A box of toffees, which was made of caramel, was kept on the table -> CORRECT

A box of toffees, which was a gift from my friend, was kept on the table -> CORRECT

You can use this as a logic to govern adjectival modifiers such as [url=
https://gmatclub.com/forum/in-a-d-391-r ... 02162.html]appositives[/url], and "which" modifiers.


Getting to your specific queries now:



Not quite - look at the examples above. We also solve some questions in the CrackVerbal GMAT Online course which have (<- note the verb here!) this concept.



Remember: use logic to dictate the rules - not the other way around.

The sword of the Maharaja of Gaipajama, found in the ruins of his palace, was sold by Rick in his pawn store --> CORRECT



This is not a rule we ever discussed - where are you picking this stuff from?



It will always modify the noun - why would it modify the clause? What made you feel that way?

I think you are over-analyzing stuff - stick to the basics!

Arun
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Dear GMATNinja,


Your explanation for option C says that - "THAT" will modify "Slot".

However, as per my understanding, That will never modify any noun in the prepositional phrase. As a results IMO, that is modifying the plural "Fossils", therefore the same is incorrect.


Please correct me if i am wrong

Regards,
Rahul Gupta

There is nothing inherently wrong with using "that" to modify a noun in a prepositional phrase (remember, there are very few concrete, black and white "rules" that you can blindly apply to GMAT SC). For example:

"I created a cartoon of a shark that lives in the ocean." - The "that" clauses clearly modifies the "shark" (the cartoon probably doesn't live in the ocean!).

Is it possible for a noun modifier to reach behind a preposition phrase? Yes (check out this post for more on that), but noun modifiers usually point to the immediately preceding noun (as described in here).

Back to choice (C): if the "that" clause DOES refer to "fossils", then we have a subject-verb agreement error (we would need, "fossils that WERE found..."). And it doesn't make sense for the "that" clause to modify sloth (as explained in this post).

Either way, (C) has to go!
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But, (D) refers "sloth", which made the deciding factor to eliminate (A)?
Or maybe we want to say the sloth in general, whereas "it" refers back to sloth which was found? I may be incorrect.

And how (A), has a non-essential modifier "and dated back..." since it has a coordinating conjunction, it doesn't seems like a non-essential modifier?

(D) sloth, found in Puerto Rico in 1991, have been dated at 34 million years old, making the sloth the earliest known mammal on

In this choice, the verb-ing modifier "making the sloth ..." is modifying either
Subject => "Fossils of the arm of the sloth" OR "Fossils"
Action => "the entire clause"

In all these cases, verb-ing modifier should make sense with the subject of the clause i.e., fossils.

But how can fossils make the sloth the earliest known mammal?

You need to be slightly nimble with your understanding Vishal.

Fossils do make the sloth the earliest known mammal, in the sense that there was something unique about these fossils (that these fossils are 34 million years old), resulting in the conclusion that the sloth (whose fossils these are) is the earliest known mammal on the Greater Antilles islands.
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Has or have been is used when an act starts in the past and progresses to the present can you explain the usage here please

Hi VS1412, you might be confusing this with present perfect continuous.

For example:

Peter has been living in US.

This is present perfect continuous (continuous indicated by the -ing form living in this case) and indicates that an act starts in the past and progresses to the present.

On the other hand, if the sentence is in present perfect:

Peter has lived in US.

This does not necessarily mean that Peter is still in US.

Similarly, have been dated, as used in this sentence, is present perfect (and not present perfect continuous).

You can watch our video on Present Perfect.
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I have two confusions.
Does "have been" Indicate past?

For option E if the "was" became "were" will option be the right answer?
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Hi! have been indicates present perfect tense.

You can watch our video on Present Perfect.


No. At the very least, an and should have been present before made, to even make it a complete sentence;

Fossils...were dated at 34 million years old, and made....
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Here's (D) as a whole:


The -ing modifer starting with "making" modifies the entire preceding clause. In other words, the fact that the fossils have been dated at 34 million years old is the thing making the sloth the earliest known mammal on Greater Antilles islands.

That makes sense, so there's no meaning issue in (D).

Compare that to (A):


Here we've got a subject ("fossils") and two modifiers ("found" and "dated"), and then we go right into our main verb ("made"). In this sentence, the fossils themselves made the sloth the earliest known mammal -- which doesn't really work. The meaning is off in (A).

And you're right that there is something funky about the modifier ", and dated back..." in (A). Generally speaking, you can use a comma+and if you've listed three or more things in a row (e.g., "I like pina coladas, getting lost in the rain, and listening to cheesy music"). You would not, on the other hand, use a comma+and if you're just listing two things (e.g., "I like pina coladas and getting lost in the rain"). (Mmm... pina coladas. )

There are only two things listed in this case, so there is no need for a comma before before "and dated." However, an extra comma isn't always treated as an error on the GMAT. For example, in this official question there is an "extra" comma in the correct answer choice.

Between the meaning issue and the comma, your best bet is to focus on the meaning issue. You can drive yourself crazy trying to check whether every comma in an SC sentence is correctly placed, and it's not worth the time. Instead, focus on higher-value errors and the meaning of the sentence.

I hope that helps!
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EMPOWERgmatVerbal daagh egmat EducationAisle

Could you please elaborate on the "On" vs. "Off" idiom issue. When is either of them preferable and why is "on" the correct idiom here or would this be a non-issue here?

Thanks

Hi fireagablast, it cannot refer to fossils, since the pronoun it can only refer to singular nouns (while fossils is obviously plural).

p.s. Our book EducationAisle Sentence Correction Nirvana discusses Pronoun eligibility. Have attached the corresponding section of the book, for your reference.

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EducationAisle
Present perfect: Present perfect is something which started in the past but still exist.
So, from the definition, it seems that 'Peter still lives in US', isn't it?
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Thanks for your question TargetMBA007!

In this case, the issue has more to do with intended meaning than strict idiom format:

...the earliest known mammal of the Greater Antilles islands. = The mammals somehow belong to/are owned by the island. It may also suggest that the people living on the island own the mammals, which is also problematic.
...the earliest known mammal on the Greater Antilles islands. = The mammals belong to no one - they just live there.

It makes a lot more sense to say that the mammals live there, rather than saying the islands/people own them. This would allow you to eliminate options A, C, & E.

We hope that helps! Please keep tagging us at EMPOWERgmatVerbal if you have any other questions!
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Hi TheUltimateWinner, I am not clear what you imply by still exist.

For example:

Michael has completed his homework.

To me, this very clearly indicates that at some unspecified time in the past, Michael completed his homework!
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EducationAisle
From the highlighted example, I just want to mean that 'Peter is still in the US'.
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Hi TheUltimateWinner, you are saying this with such confidence, as if you know Peter

Well..well....I am afraid that Peter has lived in US does not necessarily mean that Peter is still in the US.

It could as well mean that at some unspecified time in the past, Peter lived in the US (but does not live there anymore).

If the intent is to state that Peter is still in the US, we will state it as such (in Simple Present tense):

Peter lives in the US.

Or in Present Perfect continuous tense:

Peter has been living in the US for 5 years.
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Here is the example of present perfect tense again.
EducationAisle has written the post.
^^ if the author deletes the above post written by EducationAisle then we have to say the following.
EducationAisle wrote the post.
But, if the post still exist above then we have to say the following.
EducationAisle has written the post.
^^ I need not to know who is EducationAisle at all.
Can you share your thought, please?
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