Digging in sediments in northern China, evidence has been gathered by

Dear bagdbmba & krakgmat,
I'm happy to respond. You are asking about (E) & (D) respectively, so I will ignore (A) & (B), which are clearly wrong.

First of all, look at the split "evidence that" vs. "evidence which" ---- which of these two is correct? See these two posts:
https://magoosh.com/gmat/2012/that-vs-which-on-the-gmat/
https://magoosh.com/gmat/2012/gmat-gramm ... modifiers/
The fact that there is no comma following the word "evidence" means that the modifier following it is a vital noun modifier, a.k.a. a restrictive modifier. The GMAT always uses "that" for restrictive/vital modifiers, and always uses "which" for non-restrictive/non-vital modifiers. Thus, the "which" is wrong here: that's one problem with (E).

Here's the larger issue. Think about it this way. Let's state the sentence without dropping any of the repeated words in parallel. Let's pretend we can't omit anything and have to state everything explicitly. Then, we would have:

Digging in sediments in northern China, scientists have gathered evidence suggesting that complex life-forms emerged much earlier than when complex life-forms were previously thought to emerge.

Clearly, that's very awkward and much too long. We are allowed to drop everything among those orange words that are a repeat or are obvious form context. The only piece that is truly different from the part before the word "than" is "previously thought", so that's all we need.

(C) ..... than previously thought. Clear, concise, unambiguous, and grammatically correct.
(D) ..... than that which was previously thought --- very wordy, and it's unclear to what the word "that" refers
(E) ..... than that previously thought -- it's unclear to what the word "that" refers.
Think about "that previously thought" --- to what does the "that" refer? What exactly is "previously thought"? What did the scientist think at an earlier time? This really refers to the verb, to the action of the verb "emerged" --- previously, scientists thought that these critters emerged later, and now the evidence suggest that they emerged earlier. The entire comparison revolves around the verb --- when did they emerge. We cannot use the pronoun "that" to refer to the action of a verb. If we want to use "that" correctly, we would have to change around the whole sentence -----

..... gathered evidence suggesting that complex life-forms had an emergence that was much earlier than that previously thought.

Now, that version is an abominable trainwreck. Even in this version, that word "that" is entirely optional --- the phrase "than previously thought" is still 100% correct by itself, but at least in this sentence, the "that" isn't absolutely wrong when it's included, because there's a clear noun antecedent. In choices (D) & (E), the word "that" is 100% wrong, because it is trying to refer to the action of a verb, which is not allowed.

This is why (C) is not only the best answer but the only possible answer.

Does all this make sense?
Mike
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With this question we can quickly home in on the 2:3 split. Notice the participial phrase beginning 'digging...'. The word that comes directly after the comma must describe who is doing the digging. Clearly it is the archaeologists, not the evidence, that is digging. Thus we can eliminate (A), (B).

Both (D) and (E) are filled with unnecessary verbiage. (D) 'than that which..' and (E) '...than that.' We simply need a phrase that modifies 'emerge.' 'That' is used to describe comparisons between nouns. 'That' is a pronoun that is used to refers to a noun. Therefore (C) is best: 'emerged...than previously thought.'
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Dear Friends,

Here is a detailed explanation to this question-

Meaning is crucial to solving this problem:
Understanding the intended meaning is key to solving this question; the intended meaning of this sentence is that scientists were digging in sediments in northern China, and they have gathered evidence suggesting that complex life-forms emerged much earlier than previously thought.

Concepts tested here: Meaning + Modifiers + Idioms + Pronouns Awkwardness/Redundancy

• In a “phrase + comma + noun” construction, the phrase must correctly modify the noun; this is one of the most frequently tested concepts on GMAT sentence correction.
• When the chronology is clear because of terms such as "before/after/when/earlier/later"…or because of clear mention of dates, use past perfect tense is not required, though not incorrect either.
• “that” is used to provide information needed to preserve the core meaning of the sentence, and the “comma + which” construction is used to provide extra information.

A: This answer choice incorrectly uses "Digging in sediments in northern China" to modify "evidence", illogically implying that the evidence was digging in sediments in northern China; the intended meaning is that scientists were digging in sediments in northern China; please remember, in a “phrase + comma + noun” construction, the phrase must correctly modify the noun. Further, Option A redundantly uses the past perfect tense verb "had...thought" in conjunction with the adverb "previously"; please remember, when the chronology is clear because of terms such as "before/after/when/earlier/later"…or because of clear mention of dates, use past perfect tense is not required, though not incorrect either. Additionally, option A uses the passive voice construction "evidence has been gathered", leading to awkwardness and redundancy.

B: This answer choice incorrectly uses "Digging in sediments in northern China" to modify "evidence", illogically implying that the evidence was digging in sediments in northern China; the intended meaning is that scientists were digging in sediments in northern China; please remember, in a “phrase + comma + noun” construction, the phrase must correctly modify the noun. Further, Option B redundantly uses the past perfect tense verb "had...thought" in conjunction with the adverb "previously"; please remember, when the chronology is clear because of terms such as "before/after/when/earlier/later"…or because of clear mention of dates, use past perfect tense is not required, though not incorrect either.

C: Correct. This answer choice correctly uses "Digging in sediments in northern China" to modify "scientists", conveying the intended meaning - that scientists were digging in sediments in northern China. Further, Option C avoids the pronoun error seen in Options D and E, as it uses no pronouns. Additionally, Option C avoids the idiom error seen in Option E, as it correctly uses "that" to refer to information that is vital to the core meaning of the sentence - the fact that the evidence suggests that complex life-forms emerged much earlier than previously thought. Besides, Option C is free of any awkwardness or redundancy.

D: This answer choice suffers from a pronoun error, as the pronoun "that" lacks a clear referent. Further, Option D uses the needlessly wordy phrase "earlier emergence of complex life-forms than that which was", leading to awkwardness and redundancy.

E: This answer choice suffers from a pronoun error, as the pronoun "that" lacks a clear referent. Further, Option E incorrectly uses "which" to refer to information that is vital to the core meaning of the sentence - the fact that the evidence suggests that complex life-forms emerged much earlier than previously thought; please remember, “that” is used to refer to information needed to preserve the core meaning of the sentence, and the “comma + which” construction is used to provide extra information. Additionally, Option E is needlessly wordy due to the use of "that", as "that" can be removed without a loss of clarity.

Hence, C is the best answer choice.

To understand the concept of "Phrase Comma Subject" and "Subject Comma Phrase" on GMAT, you may want to watch the following video (~1minute):



To understand the concept of "Which" vs "That" on GMAT, you may want to watch the following video (~2 minutes):



All the best!
Experts' Global Team
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Modifier "Digging in sediments in northern China" should change anything that comes after it.So here evidence is being modified by this phrase but that is clearly not the intended meaning.Evidences can not themselves dig something rather scientists are digging up evidences.This leaves us with choice (C) (D) and (E)

(C)Perfectly written.Present perfect and then Past tense.Earlier error of Past Perfect has been taken care of.
(D)As per 'VAN' rule Verb Adjective/Adverb and then Noun.We have a verb that is there in the option C also "than that which was" is totally confusing
(E)Same as D.Also "than that" is not properly construct

Digging in sediments in northern China, evidence has
been gathered by scientists suggesting that complex
life-forms emerged much earlier than they had
previously thought.

(A) evidence has been gathered by scientists
suggesting that complex life-forms emerged
much earlier than they had
(B) evidence gathered by scientists suggests a
much earlier emergence of complex life-forms
than had been
(C) scientists have gathered evidence suggesting
that complex life-forms emerged much earlier
than
(D) scientists have gathered evidence that suggests
a much earlier emergence of complex life-forms
than that which was
(E) scientists have gathered evidence which
suggests a much earlier emergence of complex
life-forms than that

@ e-GMAT,
Please clarify the doubts I've on this question -

I'm not able to understand why C is preferred over E?
IMO, in option E -emergence of complex life-forms actually (per the evidence) is compared to that previously thought. It seems more clear to me where as option C sounds better but misses 'that' I guess.

Please explain.

Thanks, bagdbmba, for posting your query here as suggested. Also, thanks to Mike for the very comprehensive response!

bagdbmba: to put it simply, when 'which' refers to the noun before it, there should be a comma between 'which' and the noun. Secondly, 'that' is incorrect in option E since it is functioning as a pronoun in this option, whereas the part after 'than' should actually refer to what the scientists had previously thought.

I hope this helps with your doubt!

Regards,
Meghna
_________________

Hi Mike,
Thanks for your detailed explanation.

I've couple of doubts in what you've mentioned -
i] You've here mentioned "The GMAT always uses "that" for restrictive/vital modifiers, and always uses "which" for non-restrictive/non-vital modifiers. Thus, the "which" is wrong here: that's one problem with (E). ". But in the first article that you've shared, in the example "1) Bartholomew doesn’t like people who talk too much." - 'who' without commas, is a restrictive modifier and this sentence is correct per GMAT. Right?

That means there are exceptions. We can't just eliminate option E because 'who' is NOT preceded by a 'comma' ?

ii] 'that' in option E refers to the emergence of complex life-forms I think and it's not verb. Right? Please clarify.

Thanks Meghna for your reply.

So what I understand from your reply is 'which' can even refer to something else (NOT noun) before it. And in that case it doesn't need to be preceded by a 'comma'. Please correct me if I'm wrong.

In comparison we mostly use 'that' as to indicate the noun replacement - as a pronoun in the second clause I think.
Let's consider this sentence : Temperature in Egypt is much higher than that in Moscow. ----> here 'that' represents 'Temperature' and is a pronoun. Right?

And 'that' in option E refers to the emergence of complex life-forms I think and it's not verb. And that's what the scientists had previously thought of...Right? Please clarify.

Hi Mike,

I haven't seen any consideration for the fact the D and E use "evidence suggesting" instead of the phrase in C.
Is this phrase acceptable?

Dear bagdbmba,
Hold on! The rules for "who" are NOT the same as the rules for "which". In the case of "who", (or "when" or "where") we have only one choice, so we have to use the same word in both restrictive and non-restrictive context, and the only thing that tells us the difference is the use of punctuation.
.... the modern house, where Frank lives. (Only one modern house exists in this context, and as it happens, Frank lives there.)
.... the modern house where Frank lives. (Frank's modern house, as oppose to any other modern house.)
With "that"/"which", we get two words, and the convention that the GMAT follows is that "that" is always used in the restrictive case (no comma), and "which" is always used in the non-restrictive case (with a comma). There are no exceptions. What happens with the other relative pronouns and adverbs is not a guide for what happens with these two words.
Does all this make sense?
Mike
_________________

Dear ronr34,
That wasn't discussed because all of these are appropriate modifiers:
...evidence suggesting X.
...evidence that suggests X.
...evidence, which suggest X.
All three of those constructions are perfectly correct. For more on participial modifiers, see:
https://magoosh.com/gmat/2012/participle ... -the-gmat/
Does all this make sense?
Mike
_________________

Thanks Mike for your excellent clarifications

I think you've missed out the somehow my second concern. Would you please help me understand the same?

Dear bagdbmba
I'm sorry to miss that. I'm happy to help.

Here's version (E) of the sentence.
(E) Digging in sediments in northern China, scientists have gathered evidence which suggests a much earlier emergence of complex life-forms than that previously thought.

The word "that" is a pronoun, and its antecedent is the noun "emergence". This is a bit tricky --- "emergence" is an "action" word, but "emerge" is the verb form and "emergence" is the noun form. As a noun, "emergence" can be the antecedent of the pronoun.

This is exactly part of what make (E) one of the less desirable answers. Whenever we use the noun-forms or adjectival forms of action words, instead of the verb-forms, that makes the sentence longer and clunkier. See:
https://magoosh.com/gmat/2013/active-verbs-on-the-gmat/

Finally, notice that the verb "suggest" can take either a noun clause or a plain noun. The noun clause properly would begin with "that" (as the OA (C) has) --- then the noun-clause, like all clauses, would have a full [noun]+[verb] structure, allowing for the use of the verb form "emerge." By contrast, choice (E) simply gives the verb "suggest" a plain noun "emergence" as a direct object.

Does all this make sense?
Mike
_________________

Hi Mike,
This time the explanation appears a bit complicated to me!!

However, I think we can right away reject E because it contains 'which' without a comma before it and GMAT doesn't allow the same as you've mentioned earlier...So, this can be sufficient reason to discard option E. Right?

Dear bagdbmba,
That's correct. The GMAT only accepts use of the word "which" for non-vital modifiers. See:
https://magoosh.com/gmat/2012/that-vs-which-on-the-gmat/
https://magoosh.com/gmat/2012/gmat-gramm ... modifiers/
On the GMAT, the word "which" always introduces a non-restrictive, non-vital modifier, and if any modifier of this sort is not set off by commas, it is wrong.
Mike
_________________

I am not clear why "that which" in d and e is wrong. let me try

"that in d and e is a kind of emergence." the emergence which is previously thought " has not clear meaning. that is why d and e is wrong.

another reason is that "that" used as pronoun normally needs parallel pattern. though we see "that" in non parallel patterns in oas in some sc problems, this usage is not prefered.

please, comment on the erors in d and e.

Dear vietmoi999,
I'm happy to help and to explain a little more about what my friend & colleague Chris said.

First of all, I am going to recommend this post:
https://magoosh.com/gmat/2013/active-verbs-on-the-gmat/
One big strike against both (D) and (E) is the use of the noun "emergence" over the verb "emerge". This is an action-word. Making action-words verbs makes a sentence direct and powerful. Making the action-words nouns or adjectives makes things indirect, lily-livered, and wordy, as is the case with both (D) & (E).

Also, consider this post:
https://magoosh.com/gmat/2013/dropping-c ... -the-gmat/
Dropping words in parallel is a very tricky issue, and the GMAT loves to test it. Consider these three constructions
(1) ... emerged earlier than previously thought. (what choice (C) has)
(2) ... emerged earlier than that which was previously thought. (similar to the ending of choice (D))
(3) ... emerged earlier than that previously thought. (similar to the ending of choice (E))
All three of those are 100% grammatically correct. There's absolutely no problem with the word "that." All three of them mean the same thing. Option #1 says this idea with the fewest words, and options #2 & #3 say the same thing with more words than needed. Saying anything with more words than needed is always wrong on the GMAT SC.

Does all this make sense?
Mike
_________________

'Which' can only refer to nouns. However, if it has a preposition before it (in phrases such as 'in which'), it should not have a comma before it.



Yes, that is correct. 'That' is a pronoun that refers to 'temperature' in this sentence.



Yes, 'that' in option E is a pronoun that refers to 'emergence', a meaning that is illogical in the context of this sentence.
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Hi egmat,
Thanks for the reply. Got you on other parts.


But can you please let me know why do you say this as highlighted above ? Please share your analysis.

Appreciate your reply.