The spike in Covid positive cases post the lockdown has decreased sign

Dear Friends,

Here is a detailed explanation to this question-
Meaning is crucial to solving this problem:
Understanding the intended meaning is key to solving this question; the intended meaning of this sentence is that since the lockdown, the spike in Covid positive cases has decreased significantly.

Concepts tested here: Subject-Verb Agreement + Meaning + Tenses + Grammatical Construction + Awkwardness/Redundancy

• 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 simple past tense is used to refer to events that concluded in the past.
• Information that is vital to the core meaning of the sentence must not be placed between two commas.

A: Correct. This answer choice correctly refers to the singular noun "spike" with the singular verb "has decreased". Moreover, Option A uses the phrase "spike in Covid positive cases", conveying the intended meaning - that since the lockdown, the spike in Covid positive cases has decreased significantly. Further, Option A correctly uses the present perfect tense verb "has decreased" to refer to an action that concluded in the past but continues to affect the present. Additionally, Option A avoids the grammatical construction error seen in Option D, as it places no information between commas. Besides, Option A is free of any awkwardness or redundancy.

B: This answer choice uses the passive construction "Covid positive cases spike", rendering it awkward and needlessly indirect.

C: This answer choice incorrectly uses the simple past tense verb "decreased" 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 only used to refer to events that concluded in the past. Further, Option C uses the needlessly wordy phrase "spike in cases which have tested positive for Covid", leading to awkwardness and redundancy.

D: This answer choice incorrectly refers to the singular noun "spike" with the plural verb "have decreased". Further, Option D incorrectly places information that is vital to the core meaning of the sentence - the fact that the spike has decreased post the lockdown - between two commas; please remember, information that is vital to the core meaning of the sentence must not be placed between two commas.

E: This answer choice alters the meaning of the sentence through the phrase "has decreased significantly in Covid positive cases"; the construction of this phrase leads to an incoherent meaning; the intended meaning is that since the lockdown, the spike in Covid positive cases has decreased significantly.

Hence, A is the best answer choice.

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



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



To understand the concept of "Extra Information Between Commas" on GMAT, you may want to watch the following video (~1 minute):



All the best!
Experts' Global Team