Two problems with "but also":

1. The complementary part "not only" is missing. However even if "not only" were there, there could be parallelism issue:
a. From 1965 on, NOT ONLY the region’s standard of living has soared, but also unemployment and prices.: Wrong - parallelism between clause (the region’s standard of living has soared) and noun phrase (unemployment and prices). Note that "have soared" in the second element of the parallel structure cannot be omitted because the word "have" does not occur in the first part of the sentence.
b. From 1965 on, NOT ONLY the region’s standard of living has soared, but also have (soared) unemployment and prices.: Correct - compares clause with clause. The word "soared" can be eliminated from the second element because the word already occurs in the first element of the parallel structure.

2. Now ignore the above error and consider that "but also" can be used without "not only" (in fact it can be, but not ideally in GMAT). Now (in option A) arises a parallelism issue ( similar to the one mentioned in 1a above.) The parallelism is between clause (the region’s standard of living has soared) and noun phrase (unemployment and prices). The part "have soared" in the second element of the parallel structure cannot be omitted because the word "have" does not occur in the first part of the sentence.

Thus option A ("but also" alone) is wrong in 2 ways.

Good question! After "but" we need a verb to have both parts parallel. So A,B and D are out. Between C and E. Here we have "from 1965 on", which means that action started in the past and is still valid. Hence we need present perfect. E is out, C is correct choice.
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I agree that an auxiliary verb is needed to keep both sides of the question parallel. Eliminate A, B and D. The first part of the sentence uses present perfect, so the second part should also. Eliminate E. It is also interesting to ask yourself when solving some questions whether there is a contrast or not in the sentence you are considering. Soaring standards of living are positive, but rising prices and unemployment are negative, so a contrast is needed. You need “but”.
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A B and D elimnated.

Need a but - C & E left.

First part of sentence contains 'has'. The event started from point in the past and continues today, thus use 'have'

Dear expert, I chose C here, but I still need a valid reason why we must write "have" or helping verb in the right hand? Why "but also" alone is not enough?

Thanks!
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Dear sayantanc2k , what a wonderful explanation! One kudo seems not enough!

Well noted for your explanation. In addition, I want to ask, how if I change the statement into :

From 1965 on, NOT ONLY the region’s standard of living has soared, BUT ALSO unemployment.

I removed the prices, so we only have one noun in right side. Is it correct that in this case, we can OMIT "has"?

Thanks a million!
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really confused between C and E, standard of living has soared which is an action, don't we need action verb did in second half also?

You would need an action verb if the tense changed. Both parts are in present perfect, so that repeating auxiliary verb is enough.

For anyone curious about the usage of "so" in this question, here is a grammar article from the Cambridge Dictionary.

"so do I", " so am I" are the idiom phrases used mostly in spoken English . in formal writen English, they are accepted. these idioms are basic and easy. we do not need to know about parallelism for this problem

you can google " so do" and " are we" ... to find a explanation of ellipsis idioms.

I thought only "DID" can be used as a pronoun to replace verbs. In C the usage of have is vague. What did the employment and prices do? This soared. Only DID can replace soared right?

In this case, "has" or "have" is not replacing a verb, what's going on is that the past participle "soared" is not repeated.

Here's the sentence created via the use of choice (C).

From 1965 on, the region’s standard of living has soared, but so have unemployment and prices.

Notice the the first clause uses the present perfect "has soared." The construction that follows "but so" is understood to include the present perfect "have soared," but in this elliptical construction, "soared" is not repeated, and so, we see only "have."

Now, here is what the sentence really conveys:

From 1965 on, the region’s standard of living has soared, but so have unemployment and prices soared.

The difference between this sentence and the version created via the use of (C), is that, unlike in this sentence, in the version created via the use of (C), the second "soared" is not present. The sentence is understood to convey "have soared" without using "soared."
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Thanks for the explanation. Could you go into a bit in which cases you would use did?

How could we change the sentence to make did work here?

Apart from the difference between did and have, the intent of the sentence was to talk about something that had started in the past, but the effect is still present

When we think on those lines of the mentioned intent

Only C wins
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Just as we use "so has" or "so have" when the original verb is in the present perfect form, we use "so did" when the original verb is in the simple past form.

So, if the original verb were not "has soared" but rather the simple past "soared," then the use of "did" would make sense, as in:

During the 1960's, the region’s standard of living soared, but so did unemployment and prices.
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Hi kchen1994, it might also be helpful to do some basic reading on the various parts of speech.

For example, Pronouns actually replace Nouns (and not verbs).

Also, did is actually a verb and can in fact, substitute for the simple past tense verb of the sentence, irrespective of the tense of the first half of the comparison sentence.

For example, following is a correct sentence:

In the article "Launch it like Steve Jobs", the author asserts that during new product launches, no one has ever captured the imagination of the customers, the way Steve Jobs did.
- The main verb is in present perfect tense (has captured), but did would stand for the simple past tense captured. So, the sentence reads:

In the article "Launch it like Steve Jobs", the author asserts that during new product launches, no one has ever captured the imagination of the customers, the way Steve Jobs captured.

p.s. Our book EducationAisle Sentence Correction Nirvana discusses this property of to do verbs. Have attached the corresponding section of the book, for your reference.

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Hi, thank you for your reply. I will take a look at the attachment you linked above.

In your example, doesn't has make the tense present perfect. no one has ever captured the imagination of the customers, the way Steve Jobs did. I am a bit confused here, because the question above uses has soared, and in yours you use has captured. What is different in these two sentences?

Hi! Let's look at the second part of the two sentences.

The original sentence intends to depict:

the region’s standard of living has soared, but so have unemployment and prices soared.

Notice that the second part is intended to be in present perfect, and hence, we cannot use did.

The sentence is my post above intends to depict:

no one has ever captured the imagination of the customers, the way Steve Jobs captured.

Notice that the second part is intended to be in simple past, and hence, we can use did.

Bottom line: did can only stand for simple past tense verb in a sentence.
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Can Anybody give logic to why other options [A,B,D,E] are wrong.

I guess just knowing why C is correct isn't the very purpose of this question.


Expert Advice needed.


From 1965 on, the region's standard of living has soared, but also unemployment and prices. A

From 1965 on, the region's standard of living has soared, and also unemployment and prices. B

From 1965 on, the region's standard of living has soared, so also unemployment and prices. D

From 1965 on, the region's standard of living has soared, but so did unemployment and prices. E


Thanks in Advance