Ice-polished rocks - MGMAT SC text clarification

[jd71119]

Ron

Can u please explain what is wrong with Option C & Option E?

I am little confused with OG Explanations. In Option E, 'now' acts as an adverb but an adverb doesn't need to be close to verb. Why is E being discarded for this reason? Is there any ambiguity associated with placement of 'now'?

Option C -> Is it wrong because 'where' doesn't have any antecedent?

I also need to understand the right option B - 'What are now temperate areas'- Can what introduce a relative clause?

Thanks
Vijay

Adverbs get some leeway, but when there are more than 1 verb (or other item it should be modifying) in a sentence, the sentence can be unclear. In this case it is wrong because:

(E) when great ice sheets existed in areas now (that are temperate)

"that are temperate" is a clause describing the areas. Since now is left out of that clause, it is modifying when the ice sheets existed. They existed now is absurd, but structurally, this is the meaning of the sentence.

As for (C), let's strip away some fluff and see what happens:

(C) when great ice sheets existed where there were areas (now temperate)

The problem isn't that "where" is misplaced, it's that the word is illogical. Ice sheets existed where there were areas? Nope.

In the correct answer "what are now X" is a lesser-used expression that expresses the same meaning as "that are now X". The difference is whether they go before or after the modifier. "that" is much more versatile (and common) in life and on the GMAT:

great ice sheets existed in (what are now temperate) areas
is the same as:
ice sheets existed in areas that are now temperate

Hi Joe, I'm not sure I understand the explanation of the "what" thing that you have given. When I try to generalize it I get results that don't seem right.
For instance. "Here are some things that I remember" using this rule, would become "Here are some what I remember things". I don't think that is an okay sentence.
Please advise. Thanks.

[vikram4689]

jd see the explanation below and let me know if you have any doubts

either "in which" or "when" can be used to modify a time/event. no difference here - red herring

1st split is "existed" vs "had existed", we need former one. -> A,D out
C is not only awkward but completely wrong. it says "where there were areas now temparate" that means as if areas that are now temparate were somewhere else - wrong because areas do not move from one place to another
E used modifier "now" incorrectly. "now" should modify "are temparate" to convey areas are now temparate but were extremely cold when ice-sheets existed. e) nonsensically says "sheets existed in areas now" - "now" modifies "existed", misplaced modifier - and separates "areas" from its modifier "that"
B is correct. see placement of "now".

Note: common notion is that "what" is often used incorrectly but here it is used correctly. "what" is used for "interrogation". asking "what are now temprate areas" would give us answer as some place/area (say alaska) that can be substituted in place of above interrogative clause, for example, ice sheets existed in alaska.

[sachin.w]

Hi Ron,
I understand that Verb tense is not a high priority on GMAT but I find SC questions missing because of this.. There's one Question in OG which tests purely on tense. don't remember the Qs number though.
How do I become better at this .. please guide .

Also, you mentioned that here in this context 'in which' and 'when 'are fine..
so,
Can 'in which' be used to replace 'when' always?

Warm Regards,

[vikram4689]

'in which' can ONLY replace 'when' if 'when' is used to modify a time period/event. if any experts sees this, please comment on my analysis post73320.html#p73320

[sachin.w]

@vikram,
'When' can only be used to refer to time/time events.. so it can be inferred from your post that 'in which' can always be used to replace 'when'

[vikram4689]

when has two uses:
a) modifying a time
during the ice-age, when almost all earth was covered with ice, living on earth was nearly impossible
the age when people will love eachother irrespective of their religion will be the age of humanity
b) contemporaneous action
when i saw the ghost, i shouted loudly
when i saw my score, i became too happy

you can replace 'when'<-->'in which' in case a) only.

[thanghnvn]

I do not know why "had done" is wrong in A.

normally, when we see "had done" we need to find a mark which can be a point of time or an event for this "had done". Here I can find the mark-"led". Why "had done" is still wrong ?

pls, help explain.

[vikram4689]

you have to establish the context. you are correct in that to use past perfect we need a past tense BUT, more importantly, that past perfect event MUST be related to past event i.e. not only both event should happen one after another but both MUST also be dependent on each other

i had eaten the cake when you arrived. -> here we need past perfect to establish that i ate the cake before your arrival
i ate the cake when you arrived. -> see how the meaning changes. this time i ate the cake at the moment you arrived

when i was 5 years old, i came to know that neanderthals were too powerful to weather harsh conditions that existed during their time and that they used to walk tens of miles in one go -> notice i used past tense throughout although neanderthals existed way before i came to know about them

now, onto our problem, existence of rocks didn't happen before any other event so we need past tense only.

let me know if you have any doubts

[thanghnvn]

you have to establish the context. you are correct in that to use past perfect we need a past tense BUT, more importantly, that past perfect event MUST be related to past event i.e. not only both event should happen one after another but both MUST also be dependent on each other

i had eaten the cake when you arrived. -> here we need past perfect to establish that i ate the cake before your arrival
i ate the cake when you arrived. -> see how the meaning changes. this time i ate the cake at the moment you arrived

when i was 5 years old, i came to know that neanderthals were too powerful to weather harsh conditions that existed during their time and that they used to walk tens of miles in one go -> notice i used past tense throughout although neanderthals existed way before i came to know about them

now, onto our problem, existence of rocks didn't happen before any other event so we need past tense only.

let me know if you have any doubts

I partly understand the problem. But how to realize that two events are dependent on each other and not dependent on each other. pls, explain more of this

[jnelson0612]

you have to establish the context. you are correct in that to use past perfect we need a past tense BUT, more importantly, that past perfect event MUST be related to past event i.e. not only both event should happen one after another but both MUST also be dependent on each other

i had eaten the cake when you arrived. -> here we need past perfect to establish that i ate the cake before your arrival
i ate the cake when you arrived. -> see how the meaning changes. this time i ate the cake at the moment you arrived

when i was 5 years old, i came to know that neanderthals were too powerful to weather harsh conditions that existed during their time and that they used to walk tens of miles in one go -> notice i used past tense throughout although neanderthals existed way before i came to know about them

now, onto our problem, existence of rocks didn't happen before any other event so we need past tense only.

let me know if you have any doubts

I partly understand the problem. But how to realize that two events are dependent on each other and not dependent on each other. pls, explain more of this

You've been given pretty good explanations here . . . what specifically do you not understand?

[jnelson0612]

Hi Ron,
I understand that Verb tense is not a high priority on GMAT but I find SC questions missing because of this.. There's one Question in OG which tests purely on tense. don't remember the Qs number though.
How do I become better at this .. please guide .

You're right: verb tense is not a high priority. Just keep a few guidelines in mind:
1) Keep the tense the same throughout if possible. Only switch tenses if you have a good reason to do so.
2) Keep the tense simple if possible (simple past, present, and perfect are preferred to past perfect and present perfect). However, use complex tenses if you need them.
3) When you see "had" and "has/have" paired with another word (particularly a past participle) start thinking about whether these complex tenses are necessary. The GMAT often uses them to create wrong answers.

[thanghnvn]

"had done" is used to show an action which finished before a past action or part time maker. This is only use of "had done" which is tested on gmat.

"had done" is not used to show an action which happen before and continue to go in to a past action or past time marker. "han been doing" do so but is not tested on gmat.

in contrast,

"have done" can be use to show an action which begin before and continue to go in to a present action/time marker.

Am I correct?, pls comment

[jnelson0612]

"had done" is used to show an action which finished before a past action or part time maker. This is only use of "had done" which is tested on gmat.

"had done" is not used to show an action which happen before and continue to go in to a past action or past time marker. "han been doing" do so but is not tested on gmat.

in contrast,

"have done" can be use to show an action which begin before and continue to go in to a present action/time marker.

Am I correct?, pls comment

Correct! Those are good explanations. :-)

[pleaman]

Pls explain the usage of 'in which' and 'when'
can we eleminate the options here on the basis of 'in which/when' split??

nope. in this case, both are fine.

If usage of both 'in which and when' is right and if option 'E' is modified to - 'when great ice sheets existed in areas that are now temperate', then between 'B' and the modified 'E', which is a better option?

if you made those changes at the end of choice (e), then it would become another correct version of the sentence. in that case, each of (b) and (e) would be just as good as the other.

Hi, guys
Could you help me. I have chosen the E answer (...when great ice sheets existed in areas NOW that are temperate'). And official comment says that "NOW" should be placed just after the verb ARE.
But does that actually the big mistake to change the position of "NOW". I think that there is no changing in the meaning of the sentence ?
Which chapter in MGMAT 8g do you recommend to reread to find other examples?

[tim]

i'm not actually sure what your question is. your post is riddled with grammatical errors that make it hard to identify what you're asking. however, it looks like you question whether the position of "now" in E is truly wrong and whether the new position is correct. the answer to both of these questions is yes..

i don't know what "8g" means or what other type of examples you are looking for, but it sounds like what might help you is a better general understanding of how sentences are constructed and where words need to be placed. you may find some help in the idioms or modifiers chapters of our sentence correction book, or you may get some benefit out of reviewing the relevant portions of the foundations of verbal book..