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Source: Official Guide for the GMAT 13th Ed. Sentence Correction; #132 Official Guide for the GMAT 2015 14th Ed. Sentence Correction; #132


Although appearing less appetizing than most of

Although appearing less appetizing than most of their round and red supermarket cousins, heirloom tomatoes, grown from seeds saved during the previous year-they are often green and striped, or have plenty of bumps and bruises-herlooms are more flavorful and thus in increasing demand.

7 Explanations


Sakin Javid


Jun 11, 2017 • Comment


Very good explanation, thanks very much

Jun 5, 2017 • Comment


Gravatar Cydney Seigerman, Magoosh Tutor

Hi Shray :) Yes, you're right that a single dash may be used in place of a semi-colon. In this case, however, we have a pair of dashes. A pair of dashes is used in place of a pair of commas or parenthesis, usually with the goal of emphasizing the information between the punctuation marks. The information given between the two punctuation marks is parenthetical, or additional information that could be removed from the sentence without affecting the structure of the main clause. So, we should be left with a complete sentence if we remove the parenthetical information off set by the dashes. As mentioned in the explanation video and other posts, we see that we are left with a run-on sentence, which is grammatically incorrect. I hope this helps :)

Nov 29, 2015 • Comment

Charles Swartz

Hi Cydney,
I have another question regarding dashes. In this SC question, the correct answer is "[...] their red and round supermarket cousins--they are often green and striped, or have plenty of bumps and bruises--heirlooms are more [...]". My question is: why is it OK to have the parenthetical talking about heirlooms immediately after "supermarket cousins"? Correct me if I'm wrong, but if the dashes were commas, this would be incorrect because "green and striped" would be modifying "supermarket cousins".
Thanks for the help,

Mar 12, 2016 • Reply

Cydney Seigerman, Magoosh Tutor

Hi Chuck,

Good question! While em dashes (the -- used in this sentence) can be used in place of a set of commas or parenthesis, that doesn't mean that we can always replace a pair of em dashes with either commas or parenthesis. In this sentence, for example, the use of commas would result in a grammatically incorrect construction, as the parenthetical information is an independent clause. And for a more straight-forward analysis of this sentence, it's easiest to ignore the parenthetical statement.

With that being said, one could argue that "they" in the clause "they are often green and striped..." could refer either to the heirloom tomatoes or their supermarket cousins. However, the context of the sentence removes this ambiguity: the non-heirloom tomatoes are referred to as the heirlooms' "round and red supermarket cousins." Therefore, it does not make sense for "they are often green and striped or have plenty of bumps and bruises" to refer to the tomatoes that we know are round and red. For that reason, we can conclude that "they" describes the heirloom tomatoes rather than the supermarket tomatoes.

I hope this clears up your doubts! If not, please let me know :)


Mar 14, 2016 • Reply



B/w B and D

You said that the D one has run on sentence formation. Is it because the B sentence has SC that it is not run on....???Otherwise both sentences have noun +verb ...

Jul 15, 2015 • Comment

Jonathan , Magoosh Tutor

Saurav, (D) is a run-on because there are two independent clauses that are not properly combined. We have "heirloom tomatoes appear..." and then "heirlooms are." We need one of the following to avoid a run-on:
1) period
2) semicolon
3) comma + conjunction

Jul 27, 2015 • Reply


Ankish Kumar

In short two independent clause needs a connector/conjunction.

Dec 21, 2014 • Comment


Ankish Kumar

I did solved this question correctly.

I first looked for SV pair. I was down to B and D.

I eliminated D because it didn't have that contrast word although.

I am still unable to understand your explanation when you say its a run on sentence with NV, NV. Can you please explain it further. Thanks!

Oct 10, 2014 • Comment

Happy to help! :)

If you ever see the form Noun + Verb, Noun + Verb, you have found a run-on sentence.

The problem is that we have two sentences that don't properly connect. Mike uses the example:

"Cats meow, dogs bark."

This is a grammar error since it doesn't have a conjunction to connect these two sentences—also known as independent clauses. We could also fix this run-on sentence with punctuation too. Here are three correct versions:

"Cats meow, and dogs bark."
"Cats meow; dogs bark."
"Cats meow. Dogs bark."

In the (D), we have a similar issue. It's just a much longer sentence. The basic structure to look at in (D), which makes it incorrect is:

"...heirloom tomatoes appear...—...—herilooms are..."

That's the N.V., N.V. structure that Mike is talking about. We have no conjunctions or punctuation to avoid this run-on error.

I hope that this helps! :D

Oct 14, 2014 • Reply


Gravatar Mike McGarry, Magoosh Tutor

May 25, 2013 • Comment

Very good explanation, thanks very much!

Feb 25, 2014 • Reply

Chandrakumar G

Good explanation. Thanks.

May 4, 2015 • Reply

Shray Taneja

Hello - is a flexible connector and can be used as a semicolon . What is wrong with use of a dash.

Nov 26, 2015 • Reply

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