Art historians are using a process known as infrared scanning in analy

Hello GMATNinja, egmat

Art historians are using a process known as infrared scanning in analyzing the Mona Lisa to determine if it has been altered since completion and if Leonardo da Vinci first sketched the figure in black, as done by many artists of the time.

(A) if it has been altered since completion and if Leonardo da Vinci first sketched the figure in black, as done
(B) if it had been altered since completion and if Leonardo da Vinci first sketched the figure in black, a practice employed
(C) whether it has been altered since completion and whether Leonardo da Vinci first sketched the figure in black, a practice employed
(D) whether it was altered since completion and whether Leonardo da Vinci first sketched the figure in black, as was done
(E) whether it had been altered since completion and whether Leonardo da Vinci first sketched the figure in black, a practice done

I have couple of questions:
1. In answer choice C and D, are the highlighted parts are both correctly used?
I suppose because of the usage of 'since completion' both of them convey same meaning.

2. For the latter part of the sentence,
A --> was done --> incorrect verb tense
B --> a practice employed --> refers to the action 'Art historians are using a process known as infrared
scanning, referred to as practice
D --> as was done --> refers to the action 'Art historians are using a process known as infrared
scanning in analyzing the Mona Lisa'. Hence incorrect, rather should refer to 'Art historians are using a process known as infrared
scanning'


Thanks a lot in advance!

1) The "since" here tells us we've got a time period that starts in the past and continues into the present, so we want to use the present perfect tense "has been altered," rather than the simple past tense "was altered." So (D) is incorrect.

2) The phrase "was done" isn't in (A). Instead, we just get the modifier ("done") with no verb. And we need a verb.

(B) has other issues, but yeah, I don't see a problem with the word "practice" here.

(D) has the verb tense issue mentioned above. It's also not clear what was done, so there's a logic/clarity issue too. Either is enough to get rid of this option.

I hope that clears things up!

Whenever you have doubt of whether vs IF choose Whether (99/ 100) times its right. (if not bad luck)
and then there is since which implies something is still going on therefore has or have should come therefore answer is C

Dear Friends,

Here is a detailed explanation to this question-

Concepts tested here: Tenses + Idioms
• “if” is used to refer to phrases that lead to a “then” clause and “whether" is used for showing alternatives; "whether" generally wins over "if" on GMAT.
• The present perfect tense (marked by the use of the helping verb “has/have”) is used to describe events that concluded in the past but continue to affect the present.
• The past perfect tense (marked by the use of helping verb "had") is used when a sentence contains two actions in the past; the helping verb "had" is used with the action in the "greater past".
• The simple past tense is used to refer to actions that concluded in the past.

A:
1/ This answer choice incorrectly uses "if" to show alternatives; remember, “if” is used to refer to phrases that lead to a “then” clause and “whether" is used for showing alternatives; "whether" generally wins over "if" on GMAT.

B:
1/ This answer choice incorrectly uses the past perfect tense verb "had been altered" to refer to an action that concluded in the past but continues to affect the present; please remember, the present perfect tense (marked by the use of the helping verb “has/have”) is used to describe events that concluded in the past but continue to affect the present, and the past perfect tense (marked by the use of helping verb "had") is used when a sentence contains two actions in the past; the helping verb "had" is used with the action in the "greater past".
2/ Option B incorrectly uses "if" to show alternatives; remember, “if” is used to refer to phrases that lead to a “then” clause, and “whether" is used for showing alternatives; "whether" generally wins over "if" on GMAT.


C: Correct.
1/ This answer choice correctly uses the present perfect tense verb "has been altered" to refer to an action that concluded in the past but continues to affect the present.
2/ Option C correctly uses "whether" to show alternatives.

D:
1/ This answer choice incorrectly uses the simple past tense verb "was altered" to refer to an action that concluded in the past but continues to affect the present; please remember, the present perfect tense (marked by the use of the helping verb “has/have”) is used to describe events that concluded in the past but continue to affect the present, and the simple past tense is used to refer to actions that concluded in the past.

E:
1/ This answer choice incorrectly uses the past perfect tense verb "had been altered" to refer to an action that concluded in the past but continues to affect the present; please remember, the present perfect tense (marked by the use of the helping verb “has/have”) is used to describe events that concluded in the past but continue to affect the present, and the past perfect tense (marked by the use of helping verb "had") is used when a sentence contains two actions in the past; the helping verb "had" is used with the action in the "greater past".

Hence, C is the best answer choice.

To understand the concept of "Simple Tenses" on GMAT, you may want to watch the following video (~2 minutes):



To understand the concept of "Present Perfect Tense" on GMAT, you may want to watch the following video (~1 minute):



To understand the concept of "Past Perfect Tense" on GMAT, you may want to watch the following video (~2 minutes):



All the best!
Experts' Global Team

Hi, egmat, everyone's talking about the past and present tense, but I have doubts about "a practice employed by ..." noun modifier, what exactly is the acting noun? "sketching the figure in black paint"?

Hello ramyasree0299,

We hope this finds you well.

To answer your query, yes; here, "a practice employed by many artists of the time" refers to the act of first sketching the figure in black.

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

In C , Are there two independent clauses just joined by a comma ?

Art historians are using a process .... One Independent clause,

A practice employed ... the second independent clause.

Please let me know why these two are not independent clauses.

Thanks

Hello mcepeci,

We hope this finds you well.

To answer your query, no; the sentence formed by Option C only contains only one independent clause, as "employed" is a past participle rather than an active verb.

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

GMATNinja EducationAisle IanStewart Is there any problem in using the phrase "as done" in option? If yes, then what is it?

Is it referring to the this action mentioned in the previous sentence and thus suggesting how artists of that time "sketched in black" or is it suggesting how other artists of that time "also sketched the Mona Lisa in black"?

And is the finite verb "was" implied here?

Please explain.

GMATNinja I have the following questions on this.

1.Why 'whether' is required instead of 'if'?
2. Why 'a practice employed' is preferred over 'as done'/'as was done'?
3."whether it has been altered since completion and whether Leonardo da Vinci first sketched the figure in black, a practice employed"

Is it fine to use two different tenses while joining two dependent clauses as the sentence above? If so, in which scenarios this could be done?

We use "if" when we're introducing a conditional scenario. For example:

"If Tim comes in off the bench, his team will lose by 30."

Notice that we have a scenario (Tim comes off the bench) and a consequence (his team loses by 30). So the use of "if" works just fine here.

We use "whether" when we're introducing multiple possibilities. Here, have another example:

"It isn't clear whether Tim is still conscious."

Here, there are two possibilities: 1) Tim is conscious and 2) He isn't conscious. So "whether" is appropriate.

In the actual SC question, there are two possibilities: 1) The painting was altered. 2) The painting was not altered. So again, "whether" is appropriate.


Meaning!

A practice that is "employed," in this context, is one that is commonly used. Something that's "done" appears to be "complete" or "finished." It makes way more sense to say that this practice was commonly used by artists at the time than to say that it was a practice "completed" at the time, so "employed" is better.


There are no rules forbidding the use of different tenses in the same sentence, so long as the tenses make sense. So that's the question you always want to ask yourself.

I hope that helps!