Geologists once thought that the molten rock known as lava : CR Archive

goalsnr

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Re: Geologists once thought that the molten rock known as lava [#permalink]

03 Jul 2008, 22:58

lionheart187 wrote:

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

Can anyone explain why B is not thr correct answer? Shouldn't the past perfect tense be used here since the molten rock known as lava was an underground remnant of Earth's earliest days had been a thought that occurred in the past? there are two past actions: thought and was.

Please explain, along with a brief description about when to use and when not to use the past perfect!!

Before Scientists thought volcanoes were X,Now they think volcanoes are Y.
We need a simple past tense and a present tense to express the idea -thought/think=know

Now if the sentence mean to say the molten rock was P before the volcano and became Q after the volcano then we need a past perfect tense and past tense to express 2 events that occured in the past at 2 different times

In the given SC, the lava was oozing out in the earth's earliest days. It isn't sppecified that lava existed before and later it oozed

I remember reading in OG that a simple past tense is preferable (whenevr possible) to a past perfect tense.

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Re: Geologists once thought that the molten rock known as lava [#permalink]

21 Jul 2008, 10:51

A is best..

scientist once that that X was Y..but now know that it is W..

we need an adverbial modifier..that usage is best in A..

B

jallenmorris

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Re: Geologists once thought that the molten rock known as lava [#permalink]

21 Jul 2008, 11:10

I originally thought A also (I saw this somewhere else too). I think the reason the answer is B is due to events happening in the past. The MGMAT guide shows events on a timeline. we are in the center and to the left is the past. I first identify the subject + verb and the tense of each verb.

First: Geologists thought. This one is tricky because "to think" is an irregular verb form. I think this is used as a past perfect tense.

Then we have "molten rock...was/had been". I believe B is correct because in the past, the scientists thought something about the past of the molten rock. In the past, when the scientists thought, they thought the rock had been an underground remnant of..."

This is tricky and I don't completely agree with the OA entirely, but this is the only explanation I could come up with.

lionheart187 wrote:

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

Can anyone explain why B is not thr correct answer? Shouldn't the past perfect tense be used here since the molten rock known as lava was an underground remnant of Earth's earliest days had been a thought that occurred in the past? there are two past actions: thought and was.

Please explain, along with a brief description about when to use and when not to use the past perfect!!

diehard4

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Re: Geologists once thought that the molten rock known as lava [#permalink]

21 Jul 2008, 11:43

just got a thought...in case sentence itself clarify sequence of events do we still have to explicitly add perfect tense as in case of this sentence "was an underground remnant of Earth's earliest days" ,earliest days make it clear that remnant where there before Geologist started to think...so do we have to use past perfect tense...

or consider this one

i was walking in the park before it started to rain
OR
i had been walking in the park before it started to rain.

which one is correct..???

diehard4

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Re: Geologists once thought that the molten rock known as lava [#permalink]

21 Jul 2008, 11:58

jallenmorris wrote:

diehard4 wrote:

just got a thought...in case sentence itself clarify sequence of events do we still have to explicitly add perfect tense as in case of this sentence "was an underground remnant of Earth's earliest days" ,earliest days make it clear that remnant where there before Geologist started to think...so do we have to use past perfect tense...

or consider this one

i was walking in the park before it started to rain
OR
i had been walking in the park before it started to rain.

which one is correct..???
That depends on what you are trying to say.

But i can't see any difference in meaning of these sentences...help... :roll:

B

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Re: Geologists once thought that the molten rock known as lava [#permalink]

21 Jul 2008, 12:04

i was walking in the park before it started to rain
OR
i had been walking in the park before it started to rain.

The difference is in what time you place the reader. The first sentence, you're placing your reader at the time you were walking in the park. Think of it like telling a story. "I was walking in the park before it started to rain. Then, from behind me came..."

The second one, places your reader at some point in the future, reflecting back on the event of you walking in the park before it started to rain.

Generally, when it makes sense, we want to place the reader in the moment, as in the first one.

mbawaters

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Re: Geologists once thought that the molten rock known as lava [#permalink]

Updated on: 21 Jul 2008, 16:20

I guess I would be in 'A' bandwagon.
*EDITED*
Someone asked why past perfect or B wasn't a prefered choice?
I guess as we all already know, when the two events in the past need to differentiated on the basis of time. For example:
The train had already left when we got to the train station.

We did not have this situation here...

Originally posted by mbawaters on 21 Jul 2008, 14:36.
Last edited by mbawaters on 21 Jul 2008, 16:20, edited 1 time in total.

zoltan

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Re: Geologists once thought that the molten rock known as lava [#permalink]

22 Jul 2008, 05:53

My bet is A.

I think we do not need to use past perfect. Would is incorrect. B and D are out. C has wrong referent. Also E is wrong, because of the usage of having.

hanumayamma

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Re: Geologists once thought that the molten rock known as lava [#permalink]

06 Aug 2008, 10:52

Good one!

I too fall into the Modifier trap and thought “A” has modifier issue because “sporadically erupting through volcanoes,” modifies days.

The trick with the sentence is: a) Unlike modifier (adjective) phrase, an adverbal modifier phrase can be positioned any where within the sentence – necessarily not nearest to the noun or action that inteds to modifty. Hold A:

B – Why to have past continuos tense when simple past is better alternative – hold it

C – Which modifier issue

D – Tone change (from was – would be?)

E – having – incorrectly modifies days

Finally between A and B:
A – earns more points than B on the basis of “adverbial modifier” and “not having to use past continuous”

stallone

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Re: Geologists once thought that the molten rock known as lava [#permalink]

06 Aug 2008, 17:40

Can anyone please explain why C is not the choice .

I saw some body writing that "which " modifier is wrong .

Can you please tell why is it wrong ?

Thanks

prateek11587

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Re: Geologists once thought that the molten rock known as lava [#permalink]

06 Aug 2008, 21:46

Can anyone please explain why C is not the choice .

I saw some body writing that "which " modifier is wrong .

Can you please tell why is it wrong ?

Thanks

'WHICH' when used in GMAT serves as a relative pronoun rather than as a modifier.It will only refer to the word preceding it ,not the entire clause..THAT'S WHY 'WHICH' IS WRONG.

lexis

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Re: Geologists once thought that the molten rock known as lava [#permalink]

20 Aug 2008, 02:22

OE for B: (B) This choice unnecessarily and incorrectly changes the simple past "was" to the past perfect "had been," which is used only when describing the earlier of two past actions. Moreover, the use of "and" here equates the geologists' false understanding of lava with the fact that it sometimes erupts through volcanoes.

I think that lava, which was an underground remnant of Earth's earliest days, erupted through volcanoes. This term is true, in fact. But I do not understand why author mentions that B makes readers misunderstand.

B

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Re: Geologists once thought that the molten rock known as lava [#permalink]

16 Apr 2014, 13:42

Ron said:::
https://www.manhattangmat.com/forums/ge ... 22-45.html

We are retiring this problem in its current form, because it has several issues.

First, as you point out, "which" is not necessarily wrong here.

Second -- and more importantly -- the ostensibly correct answer to this problem doesn't actually work.
In choice A, the modifier "sporadically erupting..." does not describe anything in the preceding part, so it doesn't make sense as a "comma + __ing" modifier (which must meaningfully describe the subject+action of the preceding sentence).
Incidentally, choice A of the Dickinson problem (OG12 #26) is wrong for exactly the same reason!

This problem is no longer in our database. It will be replaced by an updated (and fully correct) version soon.

Because the problem is no longer in the database, this thread is now retired.

Thanks.

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Re: Geologists once thought that the molten rock known as lava [#permalink]

16 Apr 2014, 13:42