The English physician Edward Jenner found that if experimental subject

Question

The English physician Edward Jenner found that if experimental subjects were deliberately infected with cowpox,  which caused only a mild illness, they are immune from  smallpox.

(A) which caused only a mild illness, they are immune from
(B) causing only a mild illness, they become immune from
(C) which causes only a mild illness, they are immune to
(D) causing only a mild illness, they became immune from
(E) which caused only a mild illness, they would become immune to

https://www.nytimes.com/1979/02/04/archives/smallpox-is-not-dead.html

The research at the Atlanta lab had its beginnings in 1796 when an English country physician named Edward Jenner found that if a person was deliberately infected with cowpox,  which caused only a mild illness, he would be immune from  smallpox. Although the practice of vaccinating people with cowpox spread quickly to other countries, smallpox maintained its hold on most of the world until the 20th century. Even after immunization against it became widespread in the industrialized nations, the majority of third‐world nations continued to suffer from it, at least until 1967, when an intensified international campaign was launched.

Jenner and Cowpox 
 
 (A) Verb ( are )

(B) Modifier / Meaning ( causing ); Verb ( become ); Idiom ( become immune from )

(C) Verb ( are )

(D) Modifier / Meaning ( causing ); Verb (became); Idiom ( became immune from )

(E) CORRECT

First glance

The beginning of each answer is either  comma-which  or  comma-causing , indicating a modifier issue. Does this modifier refer just to the main noun before it or to the entire preceding clause?
 
  Issues

(1) Modifier / Meaning:  causing

In this problem, the issue that you spotted during the first glance might be a little tricky. Decide whether you want to start there or whether you want to start with anything else that you may have noticed as you read the original sentence.

Does the modifier ( which caused only a mild illness ) refer just to the main noun before it, cowpox? Or does the modifier ( causing only a mild illness ) refer to the entire preceding clause ( if subjects were deliberately infected )?

If the modifier were referring to the entire previous clause, then the sentence would be saying that  deliberately infecting  someone causes  only a mild illness , implying that the disease would be more severe if people caught it naturally. This is illogical; either way, the person still has the same disease. The modifier must be referring just to the noun  cowpox . Eliminate choices (B) and (D) for an illogical meaning.

(2) Verb:  are; become; became

The non-underlined portion of the sentence sets up a conditional structure:  If subjects were deliberately infected ...then what?

For the second half, answers (A), (B), and (C) use a present-tense verb ( are  or  become ).  Were  is in past tense, however, so present tense doesn't match. Eliminate choices (A), (B), and (C).

Choice (D) does use the simple past tense  became , but even simple past is not good enough here. The  were  verb in the conditional structure indicates that the sentence is discussing an event that may or may not happen. This second action is conditional on the first action having already happened:  If  someone  were  deliberately infected, then that person  would become  immune. Eliminate (D) for a faulty verb tense match as well.

(3) Idiom:  become / became immune from

The choices switch between  immune from  and  immune to . Which is correct?

In general,  immune to  is acceptable to use. It is sometimes possible to use  immune from , but  become immune from  is not acceptable. When using the word  become , say  become immune to . Eliminate choices (B) and (D) for a faulty idiom.

Note that answer (A) uses  immune from  but does not contain a form of the word  become . This can arguably be acceptable; the OG solution does not call this out as incorrect, so assume that it is okay for the purposes of the GMAT.

The Correct Answer

Correct answer (E) uses the noun modifier structure  which caused  to refer to the noun  cowpox . This choice also uses the correct verb tense to finish the conditional structure:  If  someone  were infected with cowpox ,  then  that person  would become immune to smallpox .

Himanshuv0 · Answer

Respected moderators
I have a different doubt in this , According to OG explanation an issue with using 'ing' modifier in option B and D has been pointed out . To quote
"The participle causing suggests that infecting subjects with cowpox caused a mild illness only in some of the cases - but this is not intended"

I am not able to understand the issue with using -ing modifier as it is a case where a participial modifier comes in the middle of sentence separated by commas, it should modify the noun ahead of it and it does so just fine

Looking forward to your help

PS - i have understood the other decision point and solved the problem correctly. It is just this point in OG ans key that is hurting me

Dear Experts,

I am facing the same issue. Can you please clear the concern?

Thanks in advance.

DmitryFarberMPrep · Answer

Himanshuv0

Yeah, that OG explanation is not very good. The team that writes the explanations is clearly not on the same level as the team that produces the questions.

Since B and D have other flaws, it’s not necessary that the -ing modifier be incorrect. “Fake” splits are common in SC! The -ing modifier makes a fair amount of sense here, but it does create a slight difference in meaning. The noun modifier in A/C/E tells us that cowpox causes a mild infection in general. So the idea is that we can infect someone with cowpox (not so bad) to prevent smallpox (a worse disease). Since B/D uses an adverbial modifier, these sentences are saying that the act of infecting someone deliberately with cowpox causes only a mild infection. This leaves open whether this is true of all cases of cowpox, or only those resulting from deliberate infection. That’s not a huge flaw in B/D, but I believe that’s what the OG explanation is trying to address.

ShantanuKejriwal · Answer

GMATNinja

Why is which caused correct in option E- Shouldnt it be, causes. My thought process is: It is a fact, and for facts simple present is used. Thanks

linuschoudhury · Answer

So we can use if and would together in a conditional statement?

EducationAisle · Answer

Oh yes, in fact, very regularly.

Our book    EducationAisle Sentence Correction Nirvana    discusses  Conditional statements , their application and examples in significant detail. If you or someone is interested, PM me your email-id; I can mail the corresponding section.

linuschoudhury · Answer

I have a hardcopy of your book, can you please tell me the page numbers?

EducationAisle · Answer

Thanks for trusting our book, for your GMAT Prep.

Conditional Constructs are covered in Chapter 7 ( Tense and Subjunctive ) in the sub-section titled "Conditional Constructs".

GMATNinja · Answer

Interesting question!

I'd say either tense is fine. You could write that cowpox  causes  a mild illness, in general. And you could also write that when certain people were infected with cowpox, the infection  caused  a mild illness, since the infections occurred in the past.

The upshot: if either construction could be justified, move on the other decision points! Fortunately, there are four nice concrete errors in this one, so there's no reason to agonize over the present vs. past tense decision.

I hope that clears things up!

lostminer · Answer

if experimental subjects  were  deliberately  infected  with cowpox... here the verb is not in simple past tense. So how can we deduce to use If..Then here?

ExpertsGlobal5 · Answer

Hello  AbhiR3 ,

We hope this finds you well.

To resolve your query, we would like to point out that "were...infected" is indeed a simple past tense verb.

We hope this helps.
All the best!
Experts' Global Team

GMATNinja · Answer

The verb "were infected" is in fact considered simple past. Note that it's a passive verb: some unknown experimenters  infected  the subjects with small pox, and the subjects  were infected  by those experimenters.

Since the experimental subjects were acted on by the verb, we need to use the passive voice. And "was/were + past participle" is the correct form for the passive simple past.

I hope that helps!

krndatta · Answer

EducationAisle 
Can you throw some light on options B and D.
Why is ,causing wrong here?
Not able to understand the solutions above.

Thanks

ExpertsGlobal5 · Answer

Hello  krndatta ,

We hope this finds you well.

Having gone through the question and your query, we believe we can resolve your doubt.

The use of "causing" slightly alters the meaning of the sentence, due to the use of the "comma + present participle ("verb+ing" - "causing" in this case)" construction; please remember, the introduction of the present participle ("verb+ing"- “causing” in this case) after comma generally leads to a cause-effect relationship.

The intended core meaning is that if experimental subjects were deliberately infected with cowpox, they would become immune to smallpox, and as extra information, it is also mentioned that cowpox causes only a mild illness.

The use of the "comma + present participle", however, implies that if experimental subjects were deliberately infected with cowpox, and doing so caused only a mild illness, they would become immune to smallpox.

We hope this helps.
All the best!
Experts' Global Team

EducationAisle · Answer

Hi  krndatta , "present participial" phrase ( causing... in this case) preceded by a comma, generally modifies the  subject  of the preceding clause.

In this case, the subject of the preceding clause is  experimental subjects . Hence, B and D convey the sub-optimal meaning that  experimental subjects  caused only a mild illness (while as per the intended meaning, "cowpox" caused only a mild illness).

Following construct would be better (though would slightly change the meaning):

if cowpox were deliberately injected into experimental subjects, causing only a mild illness...

p.s. Our book    EducationAisle Sentence Correction Nirvana    discusses  "present participial phrases" , their application and examples in significant detail. If you or someone is interested, PM me your email-id; I can mail the corresponding section.

waytowharton · Answer

KarishmaB   MartyTargetTestPrep  and other experts

In option D, Can't we consider, "causing only a mild illness" in between 2 commas and as a non-essential modifier modifying cowpox? In such a case the error that it modifies preceding clause will not hold true. What is the flaw in my undertstanding?

KarishmaB · Answer

Verb-ing after a comma at the end of the clause modifies the entire previous clause. Hence, we cannot consider that it is modifying just cowpox. 
Besides, the non underlined part is using the second conditional (past tense in 'if' clause) so we should use 'would' in 'then' clause.

Also, 'immune to' and 'immune from' are normally used in different contexts (though this wouldn't be the deciding factor): 
immune to a disease - not susceptible
immune from punishment - exempt

Answer (E)

ExpertsGlobal5 · Answer

Hello  waytowharton ,

We hope this finds you well.

To answer your query, in Option D, the phrase "causing only a mild illness" follows the "Comma + Present Participle ("verb+ing" - "causing" in this sentence)" construction, so it modifies not the preceding noun, but the entire preceding clause, typically conveying a cause-effect meaning.

Thus, even if we take it as extra information, this phrase changes the sentence's intended meaning.

We hope this helps.
All the best!
Experts' Global Team

PranayJha · Answer

Hi,

I rejected the choice E because it uses "which caused" which I thought is incorrect because Cowpox causes mild illness should be the correct as it is stating a fact and general information here, hence, shouldn't it be using present tense to state facts or general information which is always true. In that sense, how is the use of past tense correct here? Also, if the use of past tense is correct, then in what all scenarios is the use of past tense is correct for facts or general information?

Thanks

GMATNinja · Answer

The sentence is talking about some research or experimentation that happened in the past -- and the cowpox mentioned in the sentence is the  specific  cowpox that was injected in subjects during that experimentation in the past. And when did that specific cowpox cause mild illness in those subjects? In the past. So the past tense ("caused") is completely reasonable here.

Unfortunately there aren't any clear-cut "rules" for this sort of thing. You just have to do your best to think about meaning and decide whether the meaning is logical -- if you aren't sure, look for other decision points.

For more on verb tenses, check out  this old video  or  this newer one .

I hope that helps!

Deep32470 · Answer

The English physician Edward Jenner found that if experimental subjects were deliberately infected with cowpox, which caused only a mild illness, they are immune from smallpox.

(A) which caused only a mild illness, they are immune from
(B) causing only a mild illness, they become immune from
(C) which causes only a mild illness, they are immune to
(D) causing only a mild illness, they became immune from
(E) which caused only a mild illness, they would become immune to

If are, then will
if were, then would. Select E

The English physician Edward Jenner found that if experimental subject

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GMAT Sentence Correction (SC - EA only) Questions

The English physician Edward Jenner found that if experimental subject

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615 to 715 in 15 Days (Ria's Strategies)

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