Bunuel wrote:
In 1983, Dr. Luc Montagnier and colleagues of La Pitie-Salpetriere Hospital and the Institute Pasteur in Paris reported
their discovery of the AIDS virus and marked the point at which the search for the vaccine began.
A. their discovery of the AIDS virus and marked the point at which the search for the vaccine began
B. their discovery of the AIDS virus and marked the point at which the search for the vaccine begins
C. his discovery of the AIDS virus, marking the point at which the search for the vaccine had begun
D. their discovery of the AIDS virus, marking the point at which the search for the vaccine had begun
E. their discovery of the AIDS virus, marking the point at which the search for the vaccine begun
OFFICIAL EXPLANATION
In 1983, Dr. Luc Montagnier and colleagues of La Pitie-Salpetriere Hospital and the Institute Pasteur in Paris reported their discovery of the AIDS virus and marked the point at which the search for the vaccine began.A. their discovery of the AIDS virus and marked the point at which the search for the vaccine began
This answer choice makes correct use of the Past Simple to describe actions that occurred in the past (and marked the point at which the search for the vaccine began). Note that both of the verbs following reported remain in the Past tense, in keeping with the rule: Once in the Past always in the Past.
While this sentence may seem to call for Past Perfect, remember to check if any action occurred before another action in the past. In this sentence, reporting, marking of the beginning of the search, and the beginning of the search all occurred at the same point in time.B. their discovery of the AIDS virus and marked the point at which the search for the vaccine begins
Incorrect.
This answer choice is grammatically incorrect. The sentence begins in the Past tense with the phrase Dr. Luc Montagnier and colleagues....reported. By default, this sentence should remain in the Past tense. The verb begins, however, is in the Present. Remember our rule:
Once in the Past, always in the Past.
C. his discovery of the AIDS virus, marking the point at which the search for the vaccine had begun
Incorrect.
This answer choice is grammatically incorrect. In this sentence, the reporting of the discovery, the marking of the beginning of the search, and the beginning of the search all occurred at the same point in time. Therefore, the Past Simple tense should be used for all actions. This answer choice, however, uses the Past Perfect (had begun).
In addition, this answer choice changes the meaning of the original sentence by replacing their with his, ascribing the discovery solely to Dr. Luc Montagnier.D. their discovery of the AIDS virus, marking the point at which the search for the vaccine had begun
Incorrect.
This answer choice is grammatically incorrect. In this sentence, reporting, marking of the beginning of the search, and the beginning of the search all occurred at the same point in time. Therefore, the Past Simple tense should be used for all actions. This answer choice, however, uses the Past Perfect (had begun).E. their discovery of the AIDS virus, marking the point at which the search for the vaccine begun
Incorrect.
This answer choice is grammatically incorrect. In the clause at which the search for the vaccine begun, there is no conjugated verb, creating a fragment. The third form (V3) verb begun must be preceded by a conjugated verb in order to create a grammatically correct clause (had begun, has begun, was begun, etc.).