Geologists once thought that the molten rock known as lava

[goelmohit2002]

Thanks Ron !!!

Can you please help clear this doubt too..as I posted above.....copy pasting again for quick reference.

"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

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.

Thanks Ron.
But can you please help understand how "having failed" is having direct effect on astonished ?

[RonPurewal]

Thanks Ron.
But can you please help understand how "having failed" is having direct effect on astonished ?

the reason M. is astonished at passing the exam is because he has already failed it so many times

[dhson1981]

Hi

C: was an underground remnant of Earth's earliest days, which sporadically erupted

I don't understand why C is wrong. In the book of Sentence correction, we have the notion of 'mission critical' modifiers.

So 'of Earth's earliest days' modifies 'underground remnant'; then 'which sporadically erupted' modifies 'an underground remnant of Earth's earliest days' ?

Thanks

[jyz2]

Hi, I have a quick question:

I thought present participle (choice A) will follow the same tense in the sentence. Since the first part of the sentence is in past, I thought the present participle is also past. Is something wrong with this logic?

Thank you so much for your help.

[bhanupra]

Hi All,

I still didn't get the logic of when to use 'having X..'

In the above example also, 'having X..' has a direct relationship with the main clause , right?

Since, its 'having ..erupted' , meaning that this is past while the intent of the sentence is that 'volcanoes' are still erupting, so this option is incorrect.

But, please the logic of when to use or not use 'having X..'

Thanks in advance.

[tim]

The "mission critical" issue is irrelevant to modifier placement here. Instead you should refer to our general rule of thumb, namely that "which" should refer to the noun immediately preceding it, in this case "days"..

Hi

C: was an underground remnant of Earth's earliest days, which sporadically erupted

I don't understand why C is wrong. In the book of Sentence correction, we have the notion of 'mission critical' modifiers.

So 'of Earth's earliest days' modifies 'underground remnant'; then 'which sporadically erupted' modifies 'an underground remnant of Earth's earliest days' ?

Thanks

[tim]

An -ing participle is not inherently past or present; it depends on the context. "I am swimming" versus "I was swimming". So the tenses aren't actually mismatched here..

Hi, I have a quick question:

I thought present participle (choice A) will follow the same tense in the sentence. Since the first part of the sentence is in past, I thought the present participle is also past. Is something wrong with this logic?

Thank you so much for your help.

[tim]

You'll often use "having X" set off by commas to demonstrate something that was a precursor to something else:

"Tim, having read this question, proceeded to answer it."

Hi All,

I still didn't get the logic of when to use 'having X..'

In the above example also, 'having X..' has a direct relationship with the main clause , right?

Since, its 'having ..erupted' , meaning that this is past while the intent of the sentence is that 'volcanoes' are still erupting, so this option is incorrect.

But, please the logic of when to use or not use 'having X..'

Thanks in advance.

[gmathanoifall2010]

What if " sporadically erupting" modifies just "lava" ? not all the clause before?

[tim]

sorry, i just noticed that this question has been asked several times but all of us have overlooked it. there is no difference at all - in fact, since the lava WAS an underground remnant, modifying either lava or the "underground remnant" phrase means you are effectively modifying them both anyway. :) so the overall analysis remains the same. i hope this helps..

[chitrangada.maitra]

I have the same doubt as Dhson here

The mission critical modifier section of the SC guide states that there are exceptions to the 'touch rule' that generally applies to 'which / who etc'

Or is option c incorrect because 'lava erupting' should be a present continuos action?

[tim]

actually, you'll often find that "which" attaches even more strongly than normal to the word immediately preceding it. this is the biggest reason why we reject C - it really looks like the "which" modifies "days"..

[gmatwork]

what is wrong with using past perfect tense - ' had been an underground remnant' - as used in choice (b). Why do we need simple past tense - was an underground remnant - ?

Aren't there two activities happening in the past - Scientists thinking and lava being an underground remnant - both in the past?

How do you know you can simply do with the simple past? Also, when you have a parallel connector such as 'but' in this case, do we care to have the same tense (simple past or past perfect) in both the parallel parts of the sentence or can we have different tenses in parallel parts of the sentence?

Also, subordinate clause that begins with the word 'that' (essential modifier). In that modifier does the word 'that' refer to the noun right before the word 'that' (similar to the case of 'which')?

[tim]

"had been" indicates that it was once an underground remnant before scientists started investigating it, but that it stopped being an underground remnant before the scientists came on the scene..

for parallelism, it is enough that you have two conjugated verbs; the tenses do NOT have to be the same (see #42 in the OG12 for an example of this)..

"that" will refer to what is right before it in most cases; in the rare cases when it refers to something earlier it will be the case that in between the "that" and what it is modifying is another modifier of the thing that the "that" is modifying..