Scientists have identified an asteroid, 2000 BF19, that is about half

Which option are you talking about? that is getting repeated in the correct option (C).

There are two concepts to learns
i) IF-Conditional: Whenever IF is used as a condition, the resulting effect of the condition will take either 'Could' or 'Would' construction.
ii) IF-Imagination: Whenever IF is being used to imagine something, the subject-verb agreement falls apart and the only verb we can use is 'were'

A. and, if it strikes Earth, it can do tremendous damage to part of the planet but
'It could do'; not 't can do'

B. and, if it would strike Earth, part of the planet could experience a tremendous amount of damage but it would
'...that is half a mile and, if it' not parallel. Also, preferred idiom would be 'If it were to...'

C. and that, if it were to strike Earth, could do tremendous damage to part of the planet but would
Correct. 'if it were' is used correctly and 'Could' and 'Would' construction is used to give the result of the condition.

D. and that, if Earth is struck by it, can do part of the planet tremendous damage, but it would
Passive voice is avoidable. i.e. if Earth is struck by it

E. and that, if it strikes Earth, it could experience a tremendous amount of damage but
Preferred idiom would be 'If it were to...' and 'could/would' is missing from the second result of the IF-Condition. i.e. '...but would'

thangvietnam nice start with the llism catch but in exam as we have to solve questions under fixed time limit we won't have much time to catch the endless possibilities . So heres the little trick /logic which might help you get to right ans everytime.
step1 We need to understand logic and meaning of option A to our best understanding .
Step2 Identify structure and try to tag options under that right grammatical structure along with keeping pronouns in check.
Step 3 eliminate each option that doesn't follow right structure .

I have observed most of times the structure used for sentences can be broadly listed as below
1)opening modifier , main clause , ending modifier (elaborating noun/action in the clause)
2)IC + comma + FANBOYS IC
3)contrast based sentences which don't need connector but must be logically connected (eg X ,so Y , while , because .., although )
4)pure llism using and .
Note- there are more structures but broadly you will see this kind more often

Now for this particular question I used below steps .
step 1 : Scientists have identified an asteroid [OKAY SO I AM EXPECTING A LIST OR SINGLE INFO ABOUT WHAT SCIENTIST FOUND]
[1st llism thing in list] that is about half a mile wide
and [INDICTAES LLISM . may be I need THAT to complete the llism ]
[2nd llism thing in list], if it strikes Earth, it [asteroid] can do tremendous damage to part of the planet
but [I SPOTTED A BUT SO I HAVE TO EITHER USE INDEPENDENT SENTENCE USING COMMA OR USE SAME MAIN SUB (ASTEROID) AND DON'T PUT COMMA THIS WOULD MEAN .... BUT WILL BE A DEPENDENT CLAUSE , WAIT A MINUTE I also see BUT is showing nice contrast in second clause only so this can't stand as IC because the contrast is about the asteroid not about what scientists found (which is main subj) so probably I am not looking for IC because usage of but fits properly ] probably not cause planetwide destruction.

STEP 2 : scan through your options
A. and, if it strikes Earth, it can do tremendous damage to part of the planet but [NO SIGN OF LLISM , usage of and shows llism is must . IF ' IT CAN DO TRE.....DESTRUCTION ' IS IC then things haven't been properly connected -Reject ]

B. and, if it would strike Earth, part of the planet could experience a tremendous amount of damage but it would [reject llism missing either use proper connector or make this finding ll to list ]

C. and that, if it were to strike Earth, could do tremendous damage to part of the planet but would [ohh I see a that which properly connects and makes nice llism ... If it were to strike earth is a modifier there is only one thing IT can refer to is asteroid meaning and grammar wise So keep this option]

D. and that, if Earth is struck by it, can do part of the planet tremendous damage, but it would [Oh that nice . can do part of the planet tremendous damage WHO CAN DO ? who is the doer ? If you are using IT after but then IT should also be mentioned before but as the BUT is part of the second clause in ll list . BUT is not and IC here so we need to make things clear who is doing what . Also note the non essential ', if Earth is struck by it,' This is removable part and once its gone there is no doer . 3) third thing you can notice about BUT here is= COMMA + BUT is trying to lure you as if its an IC .. IC never uses WOULD . using would makes the clause dependent . meaning wise we already know that IC can't be a fact listed by scientists - Reject ]

E. and that, if it strikes Earth, it could experience a tremendous amount of damage but [complete meaning error . the asteroid won't experience damage the earth would - Reject ]

Clear winner is C . This analysis shouldn't take more than 1 minute . Hence its important to observe opt A and then attack other options .

GMATNinja could you help explain... I saw a few explanations here but not sure if I understood the difference between A/C.... redundant pronoun?
missing subject in the then clause does not sound too great either...although sound is never a good indicator for GMAT SC.

Hi Experts

Good Morning

GMATNinja VeritasKarishma EducationAisle ChrisLele mikemcgarry AjiteshArun egmat sayantanc2k RonPurewal DmitryFarber MagooshExpert avigutman EMPOWERgmatVerbal MartyTargetTestPrep other experts

Can anyone please explain me what is the difference between hypothetical subjunctive construction and If (Past tense)...Then(simple past tense or would) construction. How we can identify that it's not the case of If(past tense)...Then(Simple past tense or would) construction and it's the case of hypothetical subjective construction

In short please explain me the difference between Option A and Option C , and also how to identify "hypothetical subjective construction"

Looks like VeritasKarishma very elegantly covered the "hypothetical subjective" part of your question, but if you want a full breakdown of (A) vs (C), check out our post from earlier in the thread.

Hi AjiteshArun sayantanc2k

In the correct answer C, the clause "could do tremendous damage" is place right next to "Earth". Isn't this incorrectly modifying the "Earth" and hence hinting that Earth is casing the damage ? What am I missing ?

Hi Namangupta1997,

Yes, could do is right next to Earth, but there are a couple of things that can help us get to the correct interpretation:

1. Option C uses a pair of commas around if it were to strike Earth. Generally, when we see a pair of commas, we treat the information inside those commas as a break in the flow of the sentence. Or, to put it another way, we can ignore that part of the sentence to check what the rest of the sentence is trying to say.

(i) Scientists have identified an asteroid, 2000 BF19, that is about half a mile wide and that, if it were to strike Earth, could do tremendous damage...

Ignoring the two elements within commas, we get
(ii) Scientists have identified an asteroid that is about half a mile wide and that could do tremendous damage...

2. Earth is the object of the infinitive to strike. Within the if-clause, it is the subject, and were is the verb. To strike is something called an infinitive (infinitives are verb forms that aren't "complete" verbs).

(iii) ... if it were to strike Earth...

Earth is the thing that could receive the strike. This makes it the object of to strike. This also makes it easier to see that could do, which is a verb, must combine with something else, because verbs need to combine with subjects.

(iv) ... that, if it were to strike Earth, could do tremendous damage... ← Here that (which points to an asteroid) is the subject of could do.

Approach (2) is fine, but (1) is probably faster, so that's the one I'd recommend.

Hi AjiteshArun,

Thanks for the clarification. Just 1 follow-up question. If "If it were to strike earth" were a part of the main clause and not enclosed in commas, then "could do tremendous damage" would directly refer to earth right ? As in that case, it would no longer be an additional information. Instead it would be a part of critical info to clearly understand the intention of the sentence.
Is my understanding correct ?

Hello Namangupta1997,

We hope this finds you well.

To answer your query, if the phrase "if it were to strike Earth" were not enclosed by commas, the sentence would be incorrect, since this phrase is a modifying phrase, specifically a conditional.

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

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