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Difficulty:
25%
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Question Stats:
69% (01:16) correct
31%
(01:24)
wrong
based on 150
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Between 1930 and 1970, more than a dozen new classes of antibiotics had been developed but in the nearly four decades since then only two more were added.
(A) antibiotics had been developed but in the nearly four decades since then only two more were added.
(B) antibiotics were being developed but in the nearly four decades since then only two were developed.
(C) antibiotics were developed but in the nearly four decades since then only two more have added.
(D) antibiotics were developed in the nearly four decades but since then only two more have been added.
(E) antibiotics were developed but in the nearly four decades since then only two more have been added.
(A) antibiotics had been developed but in the nearly four decades since then only two more were added.
(B) antibiotics were being developed but in the nearly four decades since then only two were developed.
(C) antibiotics were developed but in the nearly four decades since then only two more have added.
(D) antibiotics were developed in the nearly four decades but since then only two more have been added.
(E) antibiotics were developed but in the nearly four decades since then only two more have been added.
31 Jan 2020, 05:48
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Dear Friends,
Here is a detailed explanation to this question-
Choice A: This answer choice incorrectly uses the simple past tense to refer to the development of new antibiotic classes since 1970; this tense usage is incorrect because the number of new vaccine classes developed is something that continues to have an effect on the present. Therefore, the correct tense to use here is the present perfect. Thus, this answer choice is incorrect.
Choice B: This answer choice repeats the same error found in Option A. Additionally, this answer choice uses the simple past continuous tense to refer to the development of new antibiotic classes between 1930 and 1970, an action that concluded in the past. Thus, this answer choice is incorrect.
Choice C: This answer choice changes the meaning of the sentence by substituting the verb "have been added" with the verb "added", implying that the antibiotic classes have somehow done the adding. Thus, this answer choice is incorrect.
Choice D: This answer choice changes the meaning of the sentence; this answer choice uses the phrase "in the nearly four decades" to refer to the time period between 1930 and 1970, rather than the time period following 1970. Thus, this answer choice is incorrect.
Choice E: This answer choice maintains proper tense use and conveys the intended meaning of the sentence. Thus, this answer choice is correct.
Hence, E is the best answer choice.
To understand the concept of "Present Perfect Tense on GMAT", you may want to watch the following video (~1 minute):
All the best!
Experts' Global Team
Here is a detailed explanation to this question-
eka9045
Between 1930 and 1970, more than a dozen new classes of antibiotics had been developed but in the nearly four decades since then only two more were added.
(A) antibiotics had been developed but in the nearly four decades since then only two more were added.
(B) antibiotics were being developed but in the nearly four decades since then only two were developed.
(C) antibiotics were developed but in the nearly four decades since then only two more have added.
(D) antibiotics were developed in the nearly four decades but since then only two more have been added.
(E) antibiotics were developed but in the nearly four decades since then only two more have been added.
(A) antibiotics had been developed but in the nearly four decades since then only two more were added.
(B) antibiotics were being developed but in the nearly four decades since then only two were developed.
(C) antibiotics were developed but in the nearly four decades since then only two more have added.
(D) antibiotics were developed in the nearly four decades but since then only two more have been added.
(E) antibiotics were developed but in the nearly four decades since then only two more have been added.
Choice A: This answer choice incorrectly uses the simple past tense to refer to the development of new antibiotic classes since 1970; this tense usage is incorrect because the number of new vaccine classes developed is something that continues to have an effect on the present. Therefore, the correct tense to use here is the present perfect. Thus, this answer choice is incorrect.
Choice B: This answer choice repeats the same error found in Option A. Additionally, this answer choice uses the simple past continuous tense to refer to the development of new antibiotic classes between 1930 and 1970, an action that concluded in the past. Thus, this answer choice is incorrect.
Choice C: This answer choice changes the meaning of the sentence by substituting the verb "have been added" with the verb "added", implying that the antibiotic classes have somehow done the adding. Thus, this answer choice is incorrect.
Choice D: This answer choice changes the meaning of the sentence; this answer choice uses the phrase "in the nearly four decades" to refer to the time period between 1930 and 1970, rather than the time period following 1970. Thus, this answer choice is incorrect.
Choice E: This answer choice maintains proper tense use and conveys the intended meaning of the sentence. Thus, this answer choice is correct.
Hence, E is the best answer choice.
To understand the concept of "Present Perfect Tense on GMAT", you may want to watch the following video (~1 minute):
All the best!
Experts' Global Team
31 Jan 2020, 07:59
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TENSES, PASSIVE VOICE
Between 1930 and 1970, more than a dozen new classes of antibiotics had been developed but in the nearly four decades since then only two more were added.
(A) antibiotics had been developed but in the nearly four decades since then only two more were added. ------ Past perfect (had been developed) is not required, as we are already mentioning that this event happened in a determined period of time (1930-1970).
(B) antibiotics were being developed but in the nearly four decades since then only two were developed. ------- Past Progressive (were being) is not required as it is a completed action that does not overlap another one.
(C) antibiotics were developed but in the nearly four decades since then only two more have added. ---------- We need the passive voice "have BEEN added", because the antibiotics cannot "add" - in other words, the antibiotics cannot perform the action but can receive it.
(D) antibiotics were developed in the nearly four decades but since then only two more have been added. ----- modifier "in the nearly four decades" is misplaced. It should modify only two more have been added".
(E) antibiotics were developed but in the nearly four decades since then only two more have been added. - ---- CORRECT
Between 1930 and 1970, more than a dozen new classes of antibiotics had been developed but in the nearly four decades since then only two more were added.
(A) antibiotics had been developed but in the nearly four decades since then only two more were added. ------ Past perfect (had been developed) is not required, as we are already mentioning that this event happened in a determined period of time (1930-1970).
(B) antibiotics were being developed but in the nearly four decades since then only two were developed. ------- Past Progressive (were being) is not required as it is a completed action that does not overlap another one.
(C) antibiotics were developed but in the nearly four decades since then only two more have added. ---------- We need the passive voice "have BEEN added", because the antibiotics cannot "add" - in other words, the antibiotics cannot perform the action but can receive it.
(D) antibiotics were developed in the nearly four decades but since then only two more have been added. ----- modifier "in the nearly four decades" is misplaced. It should modify only two more have been added".
(E) antibiotics were developed but in the nearly four decades since then only two more have been added. - ---- CORRECT
