Rock samples

[kramacha1979]

GPrep SC

Rock samples taken from the remains of an asteroid about twice the size of the 6 mile wide asteroid that eradicated the dinosaurs has been dated to be 3.47 billion years old and thus is evidence of the earliest known asteroid impact on Earth

A ) Same

B) has been dated at 3.47 billion years old and thus

C) have been dated to be 3.47 billion years old and thus are

D) have been dated as being 3.47 billion years old and thus

E) have been dated at 3.47 billion years old and thus are

I killed A,B for S-V issues , D lacking a verb are .. and thus evidence is awkward

Between C and E, chose C
OA : E

Q1 ) Why E not C
Q2) If I want to cut out the extra info that the GMAT likes to add in this sentence ...how should I go about to get to the core of the sentence..

Like I have seen some of Ron's explanations that essentially cuts out the flesh and gets to the bone....
thanks

[RonPurewal]

Q1 ) Why E not C

the only difference between (c) and (e) is idiomatic expression.
you don't say "dated to be..."; you do say "dated at...".

like other idiomatic expressions, this is one of those things that doesn't go according to any sort of logical rule; you just have to know it.
you should dedicate a page or two of a notebook to this, or make some flash cards for the ones you don't know.

Q2) If I want to cut out the extra info that the GMAT likes to add in this sentence ...how should I go about to get to the core of the sentence..

Like I have seen some of Ron's explanations that essentially cuts out the flesh and gets to the bone....
thanks

remember, the basic deal is that you want to get rid of anything that basically functions as a DESCRIPTOR.
i.e., a modifier that just tells you more about some particular word in the sentence.
these descriptors usually, but not always, take one of the following forms:
* prepositional phrases
* modifiers starting with participles (examples: taken from..., held in..., known to be..., taking part in...)
* appositive phrases (usually noun- or adjective-based phrases set off by commas on either side)

in this case,
taken from the remains of an asteroid about twice the size of the 6 mile wide asteroid that eradicated the dinosaurs
is one giant descriptor.
the part starting with "about twice..." is actually a descriptor within a descriptor, as it describes "an asteroid" (which itself is already within a descriptor).

if you eliminate this, you get "rock samples have been dated...", which is the core of the sentence.

[dhingra_gaurav007]

Q1 ) Why E not C

the only difference between (c) and (e) is idiomatic expression.
you don't say "dated to be..."; you do say "dated at...".

like other idiomatic expressions, this is one of those things that doesn't go according to any sort of logical rule; you just have to know it.
you should dedicate a page or two of a notebook to this, or make some flash cards for the ones you don't know.

Q2) If I want to cut out the extra info that the GMAT likes to add in this sentence ...how should I go about to get to the core of the sentence..

Like I have seen some of Ron's explanations that essentially cuts out the flesh and gets to the bone....
thanks

remember, the basic deal is that you want to get rid of anything that basically functions as a DESCRIPTOR.
i.e., a modifier that just tells you more about some particular word in the sentence.
these descriptors usually, but not always, take one of the following forms:
* prepositional phrases
* modifiers starting with participles (examples: taken from..., held in..., known to be..., taking part in...)
* appositive phrases (usually noun- or adjective-based phrases set off by commas on either side)

in this case,
taken from the remains of an asteroid about twice the size of the 6 mile wide asteroid that eradicated the dinosaurs
is one giant descriptor.
the part starting with "about twice..." is actually a descriptor within a descriptor, as it describes "an asteroid" (which itself is already within a descriptor).

if you eliminate this, you get "rock samples have been dated...", which is the core of the sentence.

Hi Ron,

I have a question on this one.
per the GMAT explanation, we need a verb after AND THUS in option D..( i know that dated being is unidomatic) but my question how to judge that we need a verb or not..
is it because its a conjunction and its joining an IC and IC..so to make second half after "AND" IC we need a verb..is this universally applicable..i mean i should check for this rule if my options are somewhat like what is mentioned above!!

thanks

[ryan.m.doyle]

Same question as above. Why do we need the verb in E?

Thanks,

Ryan

[RonPurewal]

Same question as above. Why do we need the verb in E?

Thanks,

Ryan

the verb is necessary because the parallelism doesn't work without it.

if the verb is not present, you have
have been dated at 3.47 billion years old and thus evidence of the earliest known asteroid impact on Earth

in this case, "evidence of the..." is the second half of the parallelism. (these words are tagged by the parallel signal "and thus", so you don't have a choice about that)
there's nothing on the left to be parallel to these words, so the parallelism doesn't work.
HOWEVER,
if you include the verb, then we have
...have been dated at 3.47 billion years old
and thus
are evidence of the earliest known asteroid impact on Earth
these are parallel.

--

if the parallelism works WITHOUT the verb, then you don't need the verb.

example:

lola is 34 years old and thus is too young to compete in the Masters division.
lola is 34 years old and thus too young to compete in the Masters division.

these are actually BOTH correct. here are the parallel structures:
lola is 34 years old and thus is too young to compete in the Masters division.
lola is 34 years old and thus too young to compete in the Masters division.

[ryan.m.doyle]

Good explanation. Thanks.

[RonPurewal]

Good explanation. Thanks.

thanks.

[at1687]

dated at 3.47 billion years old?

Shouldn't this just be 'dated at 3.47 billion years'?

I realize that the answer options don't present this, so this still may be the 'best option to choose'.

[RonPurewal]

dated at 3.47 billion years old?

Shouldn't this just be 'dated at 3.47 billion years'?

I realize that the answer options don't present this, so this still may be the 'best option to choose'.

yeah, i don't love that either, but GMAC is the king of the playground here.

[Suapplle]

sorry to restart the thread
I have a question about this problem, please help.
I read Ron's comment about the "estimate at & estimate to be",I cannot find the original post, but there are my notes:

* "at" is a preposition.
* prepositions must be followed by nouns.
* "xxx number of years old" is not a noun.
so, wrong.

in the other example -- "temperatures estimated at xxxx degrees fahrenheit" -- there's no problem, because "xxxx degrees fahrenheit" is a noun.

i don't think anything else is happening here.
the OG explanations are wrong fairly regularly (though not in most cases); this is one of those times.]

why" date at +xx years old" is correct while "estimate at xx years old" is incorrect? and why xx years old is not a noun?
I am really confused,please help me,thanks a lot!

[RonPurewal]

sorry to restart the thread
I have a question about this problem, please help.
I read Ron's comment about the "estimate at & estimate to be",I cannot find the original post, but there are my notes:

* "at" is a preposition.
* prepositions must be followed by nouns.
* "xxx number of years old" is not a noun.
so, wrong.

in the other example -- "temperatures estimated at xxxx degrees fahrenheit" -- there's no problem, because "xxxx degrees fahrenheit" is a noun.

i don't think anything else is happening here.
the OG explanations are wrong fairly regularly (though not in most cases); this is one of those times.]

why" date at +xx years old" is correct while "estimate at xx years old" is incorrect? and why xx years old is not a noun?
I am really confused,please help me,thanks a lot!

Yeah, I wouldn't have expected the way they wrote this problem, either. But, if they put it in a correct answer, we just have to smile and accept it.

The likelihood that a strange idiom like this one will be tested on the current version of the GMAT is essentially zero, so, if I were you, I wouldn't worry about it.

[Suapplle]

sorry to restart the thread
I have a question about this problem, please help.
I read Ron's comment about the "estimate at & estimate to be",I cannot find the original post, but there are my notes:

* "at" is a preposition.
* prepositions must be followed by nouns.
* "xxx number of years old" is not a noun.
so, wrong.

in the other example -- "temperatures estimated at xxxx degrees fahrenheit" -- there's no problem, because "xxxx degrees fahrenheit" is a noun.

i don't think anything else is happening here.
the OG explanations are wrong fairly regularly (though not in most cases); this is one of those times.]

why" date at +xx years old" is correct while "estimate at xx years old" is incorrect? and why xx years old is not a noun?
I am really confused,please help me,thanks a lot!

Yeah, I wouldn't have expected the way they wrote this problem, either. But, if they put it in a correct answer, we just have to smile and accept it.

The likelihood that a strange idiom like this one will be tested on the current version of the GMAT is essentially zero, so, if I were you, I wouldn't worry about it.

Ron,thanks a lot!
so,generally，"at" should be followed by a noun,"date at xx years old"is just an exception.is such interpretation right?

[RonPurewal]

That's my understanding.

[manhhiep2509]

the verb is necessary because the parallelism doesn't work without it.

if the verb is not present, you have
have been dated at 3.47 billion years old and thus evidence of the earliest known asteroid impact on Earth

in this case, "evidence of the..." is the second half of the parallelism. (these words are tagged by the parallel signal "and thus", so you don't have a choice about that)
there's nothing on the left to be parallel to these words, so the parallelism doesn't work.

Hello Ron.
Do you mean that because "dated" is a adj and "evidence" is a noun -- the two words are not the same part of speech -- the two phrases are not parallel without the verb "are"?

If I interpreted the choice in below way, what is wrong?
... have been dated as being 3.47 billion years old
and thus have been evidence ...
If I thought in this way, I would explain that because "have been" is repeated so the author removed one to avoid redundancy.

Please clarify my confusion.

Thank you.

[RonPurewal]

They are evidence (and they will be, in perpetuity). "Have been" is inappropriate for that.

You also can't write "The earth has been round".