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Here is a detailed explanation to this question-
quiet888 wrote:
Astronomers have uncovered evidence that a star that was as bright as the full moon exploding into view 340.000 years ago, emitting dazzling radiation that could have disrupted Earth's protective ozone layer and sunburned our Stone Age ancestors.
(A) that a star that was as bright as the full moon exploding into view 340,000 years ago, emitting
(B) that a star as bright as the full moon exploded into view 340,000 years ago, emitting
(C) of a star that was as bright as the full moon exploding into view 340,000 years ago and that it emitted
(D) of a star as bright as the full moon, exploding into view 340,000 years ago and emitting
(E) of a star as bright as the full moon that exploded into view 340,000 years ago and that emitted
Meaning is crucial to solving this problem:Understanding the intended meaning is key to solving this question; the intended core meaning of this sentence is that astronomers have uncovered evidence that a star that was as bright as the full moon exploded into view 340,000 years ago and as a result, emitted dazzling radiation.
Concepts tested here: Meaning + Verb Forms + Awkwardness/RedundancyA: This answer choice fails to form a complete sentence; as "exploding" and "emitting" are noun modifiers, there is no active verb to act upon the subject noun "star".
B: Correct. This answer choice acts upon the independent noun "star" with the active verb "exploded" to form a complete thought, leading to a complete sentence. Further, Option B uses the phrase "emitting dazzling radiation", conveying the intended meaning - that astronomers have uncovered evidence that a star that was as bright as the full moon exploded into view 340,000 years ago and as a result, emitted dazzling radiation; please remember, the introduction of the present participle ("verb+ing" - "emitting" in this sentence) after comma generally leads to a cause-effect relationship. Additionally, Option B is free of any awkwardness or redundancy.
C: This answer choice alters the meaning of the sentence through the phrase "and that it emitted"; the use of "and" incorrectly implies that a star that was as bright as the full moon exploded into view 340,000 years ago and
as a separate action, emitted dazzling radiation; the intended meaning is that a star that was as bright as the full moon exploded into view 340,000 years ago and
as a result, emitted dazzling radiation. Further Option C uses the needlessly wordy phrase "of a star that was as bright as the full moon", leading to awkwardness and redundancy.
D: This answer choice alters the meaning of the sentence through the phrase "exploding into view 340,000 years ago and emitting"; the use of the "comma + present participle ("verb+ing" - "exploding" and "emitting" in this sentence)" construction illogically suggests that astronomers have uncovered evidence of a star that is currently as bright as the full moon, and as a result, the astronomers exploded into view 340,000 years ago and emitted dazzling radiation; the intended meaning is that astronomers have uncovered evidence that a star that was as bright as the full moon exploded into view 340,000 years ago and as a result, emitted dazzling radiation; please remember, the introduction of the present participle ("verb+ing" - "exploding" and "emitting" in this sentence) after comma generally leads to a cause-effect relationship.
E: This answer choice alters the meaning of the sentence through the phrase "and that emitted"; the use of "and" incorrectly implies that a star that was as bright as the full moon exploded into view 340,000 years ago and
as a separate action, emitted dazzling radiation; the intended meaning is that a star that was as bright as the full moon exploded into view 340,000 years ago and
as a result, emitted dazzling radiation.
Hence, B is the best answer choice.To understand the concept of "Comma + Present Participles for Cause-Effect Relationships" on GMAT, you may want to watch the following video (~3 minutes):
All the best!
Experts' Global Team
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