Geologists once thought that the molten rock known as lava

[Shib]

Source:Manhattan Gmat Test

Geologists once thought that the molten rock known as lava was an underground remnant of Earth's earliest days, sporadically erupting through volcanoes, but they now know that it is continuously created by the heat of the radioactivity deep inside the planet.

A. was an underground remnant of Earth's earliest days, sporadically erupting
B.had been an underground remnant of Earth's earliest days and sporadically erupted
C.was an underground remnant of Earth's earliest days, which sporadically erupted
D.would be an underground remnant of Earth's earliest days that sporadically erupted
E.was an underground remnant of Earth's earliest days, having sporadically erupted


My doubt is, isn't "sporadically erupting" modifying the "earliest days"? I maybe wrong, but how do I identify when a cluase is getting modified or when is the noun preceeding it.I'm confused in this concept and please help.

[StaceyKoprince]

Haven't forgotten about you Shib! I'm checking something on this one.

[StaceyKoprince]

Okay, sorry for the delay in answer you! The "ing" ending of erupting essentially allows this modifier to modify an entire clause instead of just the immediately preceding noun (which is the case, for example, in answer choice C - the "which" makes it a noun modifier and it would have to modify "days"). Which, who, where - all of those indicate noun modifiers (and noun modifiers, by definition, have to touch the noun they modify).

[Guest]

What is OA?

[StaceyKoprince]

OA is A

[mridul12]

Thanks Stacey,

That explanation is very useful
I have a question about answer choice E

Answer choice E) has a participial phrase with past participle (having PLUS erupted) and an action in the past (thought). This makes it a past perfect tense. Also, it modified the entire clause. Any reason why this is wrong OR may be my logic is wrong.

Please comment.

[StaceyKoprince]

"having erupted" isn't actually the past perfect tense; it is the relative past tense. Past perfect is constructed with "had" and the past participle. "having erupted" indicates that the eruption occurred at a time prior to the other past tense verb, thought.

Now, it could be true that the eruptions only occurred prior to when the geologists thought whatever they thought - but that's not the original meaning given by the sentence. The original sentence indicates that the lava is still erupting, and we have to maintain the original meaning unless there is an actual logical flaw that needs to be corrected for the sentence to make sense.

[mridul12]

Great explanation, Stacey!

It seems like we have to look for the original meaning of the sentence (of course with correct grammar) before deciding an answer. Do you know if GMAT can ask to pick the answer without considering its context relative to original meaning of sentence? For example, if they ask us to decide between the following two choices:

A) Having glanced at the newspaper, I laid it aside.

B) I had glanced at the newspaper and laid it aside.

What is the difference between the two sentences?

I am assuming GMAT will give an answer with a notable difference either in grammar or the meaning in context.

Regards.

[Guest]

Hi
Can you explain why it is NOT "sporadically erupted"? I thought it was paralled with "continuously created"

I picked answer choice B the first time around. Thanks!

[StaceyKoprince]

If the GMAT bases a wrong answer on a meaning difference, it will be very clear that it is following the meaning of the original sentence. Now, that doesn't mean we'll always notice it - they're pretty good at getting us not to notice things - but if you do notice, you won't be debating about what the original meaning was that needs to be maintained in the right answer.

Re: the parallelism question, be careful about using parallelism just because you want to. A logical reason / rule actually has to exist that requires parallelism in the sentence - a list, an idiom, or reference to the same single noun or verb. This sentence introduces a new clause with "it is continuously created" so there is no need for parallelism here. In addition, we need the -ING form of erupting in order to construct the modifier correctly.

[shobuj40]

is this will be correct answer if i write this sentence :

Geologists once thought that the molten rock known as lava was an underground remnant of Earth's earliest days that sporadically erupted volcanoes, but they now know that it is continuously created by the heat of the radioactivity deep inside the planet.


what is that refering here
thanks

[JonathanSchneider]

The word "that" is not clear enough to the word "rock" here. "That" is next to "days," but even that is not the real problem. Before "days" we have "remnants," and it sounds as though "that" is modifying "remnants." (This would probably be okay, even though the "that" is not right next to it; you can't just say "remnants" without describing the remnants - remnants of what? - first.) You mean for "that" to modify "rock."

The bigger problem is that you're using "erupted" as a transitive verb, aka a verb that takes a direct object. "Erupted volcanoes" sounds as though the rock (or whatever you mean "that" to refer back to) affected the volcanoes. "Erupted through volcanoes" would be better.

[goelmohit2002]

Okay, sorry for the delay in answer you! The "ing" ending of erupting essentially allows this modifier to modify an entire clause instead of just the immediately preceding noun (which is the case, for example, in answer choice C - the "which" makes it a noun modifier and it would have to modify "days"). Which, who, where - all of those indicate noun modifiers (and noun modifiers, by definition, have to touch the noun they modify).

Hi Stacey,

Thanks. But the OE said that:

"Moreover, the modifier "sporadically erupting through volcanoes" correctly modifies "an underground remnant of Earth's earliest days."

Looks to be different from your opinion...can you please tell what indeed is the case ?

[goelmohit2002]

"having erupted" isn't actually the past perfect tense; it is the relative past tense. Past perfect is constructed with "had" and the past participle. "having erupted" indicates that the eruption occurred at a time prior to the other past tense verb, thought.

Hi Stacey,

Thanks a lot !!

But the same is the case with past perfect....isn't it.....in two past tenses...the first one is told by past perfect...then what is the difference between having + simple past
and had + simple past ?

Kindly help !!!

Thanks
Mohit

[RonPurewal]

"having erupted" isn't actually the past perfect tense; it is the relative past tense. Past perfect is constructed with "had" and the past participle. "having erupted" indicates that the eruption occurred at a time prior to the other past tense verb, thought.

Hi Stacey,

Thanks a lot !!

But the same is the case with past perfect....isn't it.....in two past tenses...the first one is told by past perfect...then what is the difference between having + simple past
and had + simple past ?

Kindly help !!!

Thanks
Mohit

hi -

you also shouldn't use "having X..." unless having X actually has a direct effect upon the action in the main clause.

example:
having failed the exam 5 times already, M. was astonished when he received a passing mark.
in this case, the relationship is clear. in the answer choice you're discussing, there is no such relationship.