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Paranthropus are a group of hominids that existed at the same time 09 Aug 2020, 06:44
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OFFICIAL EXPLANATION

Project SC Butler: Sentence Correction (SC1)


THE PROMPT
Quote:
Paranthropus are a group of hominids that existed at the same time as the Australopithecines and some other species of the Homo genus.
This question tests verb tenses, logic, parallelism, and ellipsis.

You could easily overthink this question.
You can avoid overthinking by moving your eyes to the next option. No kidding.

Our goal is to eliminate the four worst answers, not to find the best answer.

THE OPTIONS
Quote:
A) Paranthropus are a group of hominids that existed at the same time as the Australopithecines and some other species of the Homo genus [existed].
• I see no errors

• Meaning? Very simple.
Paranthropus, Australopithicus, and "some other" hominid species all existed at the same time.

• The word existed does not need to be repeated.

→ In English, in the second part of a sentence, we frequently do not repeat simple verbs.
Correct: Samuel cooks breakfast more often than Safia.
Meaning: Samuel cooks breakfast more often than Safia cooks breakfast.
-- The verb in this sentence is simple: existed.

→ when can we omit a verb or verb phrase? On the GMAT, very frequently and as long as the sentence still makes sense.
Original: Kenyatta arrived at the same time as Samuel arrived.
Ellipsis, verb implied is in brackets: Kenyatta arrived at the same time as Samuel [arrived].

• In this sentence, existed is implied and if written, would be placed after Homo genus as I have indicated.
KEEP
Quote:
B) Paranthropus are a group of hominids that had existed at the same time as had the Australopithecines and some other species of the Homo genus.
• had existed is incorrect in both instances
→ we use the past perfect tense had existed to depict the earlier of two past events
→ These groups—Paranthropus, Australopithecines, and "some others"—existed at the same time.

→ In addition, we do not use past perfect (had + __ED) when simple past will suffice
Wrong: He had relocated recently.
Correct: He relocated recently.
ELIMINATE B
Quote:
C) Paranthropus are a group of hominids that existed at the same time as had the Australopithecines and some other species of the Homo genus.
• we cannot use had (coupled with the Australopithecines) as a substitute for existed (coupled with that, referring to Paranthropus)

→ IF the original verb contains had, then we can repeat just the "had" part later in the sentence
Correct: When the train lurched, people in the aisles stumbled, but I had sat down by then, as had Daniel.

→ If the original verb does not or should not contain had and we want to repeat a shortened verb phrase, we use did or did so.
Correct: The train seemed unsteady, so I put my phone away, as did Daniel.

• had is not needed because past perfect is inappropriate, and
• had cannot be used as a substitute for existed
ELIMINATE C

Quote:
D) Paranthropus are a group of hominids existing at the same time as the Australopithecines and some other species of the Homo genus.
• existing does not fit with the timeline in which at least three hominid groups existed at the same time

• we speak about general truths with present tense verbs such as are, but because we are talking about a historical fact, the present participle existing is confusing.
→ In order fix what seems like "tense hopping," existing should be changed to who existed
ELIMINATE D
Quote:
E) Paranthropus are a group of hominids existing at the same time as were the Australopithecines and some other species of the Homo genus.
• existing does not fit with the timeline in which at least three hominid groups existed at the same time

• we speak about general truths with present tense verbs such as are, but because we are talking about a historical fact, the present participle existing is confusing, especially when set next to "were the Australopithecines. . .
→ In order fix what seems like "tense hopping," existing should be changed to who existed

• what is this "were" word supposed to be doing? What verb is were drawing upon?
→ no were existing is present.
-- We cannot repeat an elided verb that never existed in the first place
-- That is, we cannot shorten were existing to were because were existing never showed up in the first place
-- Besides, were existing is horrible English 99.9 percent of the time and you will never see were existing on the GMAT
ELIMINATE E

Notes

→ → Past perfect
Past perfect is often described as "the past of the past."

Event ABC happened in the past.
Before event ABC, event XYZ happened:

← --[XYZ] --->-->-----[ABC] ---->----> now

Event ABC takes simple past verb tense.
Event XYZ takes past perfect verb tense.

→ past perfect construction: HAD + past participle (verbED)
→ Correct: Luckily, I remembered before I drove very far from home that I had forgotten to lock the door.

→ We do not use past perfect when simple past tense will suffice.

→ Finally, in order to use past perfect, the sentence must contain at least one event that is rendered in simple past, or a time stamp that marks off a later-in-time event, or a context that does the same thing.
We need a discrete past "marked off in time" in order to talk about what came before that time.

AS

KaramveerBakshi , in answer to your question, first

→ As is not always followed by a clause.
Role: She went to the Halloween party dressed as Neytiri from Avatar.
Equals: Though we are not related, I think of her as my sister.
Stage: As a teenager, he contracted chicken pox.

→ We can omit verbs and the implied verbs are still "there," as are the clauses

On this point, I am going to quote Mike McGarry, because he gets away with a lot more snark than I, at least for now:

Quote:
Parallelism: A told B about X at lunch on Monday, and about Y on Wednesday, but on Friday C told A that X and Y are not true.

Is this correct? YES! Is the part “.. and about Y on Wednesday …” a full clause? YES. It is a full clause, properly in parallel, despite the fact that many common words, including the subject and verb of this clause, have been omitted. Don’t look at one little piece of real estate in the sentence and conclude: something’s wrong here, because I don’t see a subject and a verb right here. You always have to look at the whole flow of the sentence, and ask yourself whether words that appear to be missing in the second branch of parallelism are implied by the first branch. Parallelism is a large organizing structure, relating different parts of the sentence to each other. (My emphasis)

KaramveerBakshi , I'm glad that you brought up the issue.
This as IS followed by a clause. The verb in that clause, existed, is implied: there, but hidden.

SUGGESTION

Parallelism and ellipsis can be challenging.

I suggest that you read two of Mike McGarry's blog posts. Three minutes each. (Okay. I read quickly. Ten minutes each.)
(1) Dropping Common Words in Parallel on the GMAT, which you can find here, and
(2) Repeating Verb Phrases on the GMAT, which you can find here.

COMMENTS

harrywm , daniformic , and Babineaux , welcome to SC Butler. :)

As always, I am glad to see everyone.

Random facts:
Today is the International Day of the World's Indigenous Peoples.
Today is also National Book Lovers Day in the U.S.
I think yesterday was National Beer Day. I don't like beer. I've tried to like beer.
I do like books. A lot. I don't have to try, either.

So, my nascent bibliophiles, I am going to remind you all yet again: read. Every day. Find 10 minutes.
Read novels. Read the highbrow stuff, but read books with great stories in them, too.

Love the task.
Or learn to love the task.
Reading? Learning? Perhaps the task even becomes a labor of love.

This SC question?
Labeling (e.g. "pronoun error") is not explanation. Assertion (e.g. "not correct") is not explanation.
Kudos go to those who reasoned well, got the correct answer, or both—and who also explained.
This question is hard. Nicely done.
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Thank You Sir generis, for depicting the difference between parallelism and ellipsis.

And the suggestion for Sir Mike McGarry's post. :)
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Paranthropus are a group of hominids that existed at the same time Updated on: 09 Aug 2020, 22:56
Originally posted by cathygeorge123 on 09 Aug 2020, 09:06.
Last edited by cathygeorge123 on 09 Aug 2020, 22:56, edited 2 times in total.
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Paranthropus are a group of hominids that existed at the same time as the Australopithecines and some other species of the Homo genus.

A) that existed at the same time as the Australopithecines
Correct: X existed at the same time Y (did). This is fine as these two entities took place in the past(moreover, simple past). This should have been fine even if X and Y were both depicted in the present.
Note: We are not presenting facts here,rather an event(to exist). generis has also provided a great example of what Einstein postulated in his post below to correct me on my striked-thru error!

B) that had existed at the same time as had the Australopithecines
Incorrect: We do not use PAST PERFECT in both part of the sentence as past perfect is used to showcase one event that happened much prior to the other.

C) that existed at the same time as had the Australopithecines
Incorrect: One entity X cannot exist at the same time as an entity Y that existed much before. It is therefore not logical to have an event in simple past and an event in past perfect at the same time.

D) existing at the same time as the Australopithecines
Incorrect: We are not talking about a fact here and at the moment X does not currently exist at the same time as Y. Exist in continuous present tense depicts an event currently happening which is not the meaning the sentence is trying to convey.

E) existing at the same time as were the Australopithecines
Incorrect: This is absolutely nonsensical as X cannot currently exist at the same time as when Y existed in the past. Eliminate!

Hope this was clear :)
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Paranthropus are a group of hominids that existed at the same time 09 Aug 2020, 22:14
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Paranthropus are a group of hominids that existed at the same time as the Australopithecines and some other species of the Homo genus.

A) that existed at the same time as the Australopithecines
Correct: X existed at the same time Y (did). This is fine as these two entities took place in the past(moreover, simple past). This should have been fine even if X and Y were both depicted in the present.
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cathygeorge123 , first, welcome to SC Butler. :)

Second, you want to be careful about the assertion I highlighted. I may not understand what you mean.

I think you believe that this sentence would be acceptable:

Paranthropus are a group of hominids that exist at the same time as the Australopithecines and some other species of the Homo genus.
That sentence is not grammatical.

GMAC follows the convention of using present tense to describe scientific facts.

But sometimes complex sentences require us to mix tenses.

The most famous example of this tense mixture is the sentence,
"In 1905, Albert Einstein postulated that the speed of light is constant. . . "

Postulated refers to an event that occurred in 1905 and is therefore written in past tense, whereas is conveys a general truth and is written in the present tense.

This tense mixing is similarly required in option A.

In (A), we cannot depict Paranthropus, Australopithecines and some other species of the Homo genus in the present, and doing so would not be fine.

The three hominid groups are extinct.
They do not exist in the present. We cannot say that they exist.

The scientific facts about them do exist in the present.

So we mix the tenses. Your comment spurred me to address an important issue. Mixed verb tenses are kinda weird.

The rest of your answers are just fine. Nicely done.
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Paranthropus are a group of hominids that existed at the same time 09 Aug 2020, 22:15
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Babineaux

Thank You Sir generis, for depicting the difference between parallelism and ellipsis.

And the suggestion for Sir Mike McGarry's post. :)
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Babineaux , you are welcome.
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Paranthropus are a group of hominids that existed at the same time 09 Aug 2020, 22:49
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cathygeorge123
Paranthropus are a group of hominids that existed at the same time as the Australopithecines and some other species of the Homo genus.

A) that existed at the same time as the Australopithecines
Correct: X existed at the same time Y (did). This is fine as these two entities took place in the past(moreover, simple past). This should have been fine even if X and Y were both depicted in the present.
cathygeorge123 , first, welcome to SC Butler. :)

Second, you want to be careful about the assertion I highlighted. I may not understand what you mean.

I think you believe that this sentence would be acceptable:

Paranthropus are a group of hominids that exist at the same time as the Australopithecines and some other species of the Homo genus.
That sentence is not grammatical.

GMAC follows the convention of using present tense to describe scientific facts.

But sometimes complex sentences require us to mix tenses.

The most famous example of this tense mixture is the sentence,
"In 1905, Albert Einstein postulated that the speed of light is constant. . . "

Postulated refers to an event that occurred in 1905 and is therefore written in past tense, whereas is conveys a general truth and is written in the present tense.

This tense mixing is similarly required in option A.

In (A), we cannot depict Paranthropus, Australopithecines and some other species of the Homo genus in the present, and doing so would not be fine.

The three hominid groups are extinct.
They do not exist in the present. We cannot say that they exist.

The scientific facts about them do exist in the present.

So we mix the tenses. Your comment spurred me to address an important issue. Mixed verb tenses are kinda weird.

The rest of your answers are just fine. Nicely done.
Show more

Thank you very much for the warm welcome :please: .Oh I see my mistake with that statement that the present tense would have been acceptable,generis! You are absolutely right! Many thanks for that and I'll put up a correction in my post so that it doesn't mislead anyone :)
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Paranthropus are a group of hominids that existed at the same time 05 Sep 2021, 15:01
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