Bunuel
After massive military preparations for Operation Barbarossa, the Axis powers were poised to conquer the Soviet Union in the summer of 1941, but their defeat at the Battle of Moscow in December of that year
reveals that they had not imagined the Red Army will mobilize troops from the vast Soviet territories.
A. reveals that they had not imagined the Red Army will mobilize troops from the vast Soviet territories
B. reveals it hadn't been imagined that the Red Army would mobilize troops from the vast Soviet territories
C. revealed that they hadn't imagined the Red Army will mobilize troops from the vast territories of the Soviet Union
D. revealed that they did not imagine that the Red Army would mobilize troops from the Soviet Union's vast territory
E. revealed that they had not imagined the Red Army would mobilize troops from the vast Soviet territories
OFFICIAL EXPLANATION
After massive military preparations for Operation Barbarossa, the Axis powers were poised to conquer the Soviet Union in the summer of 1941, but their defeat at the Battle of Moscow in December of that year reveals that they had not imagined the Red Army will mobilize troops from the vast Soviet territories.A. reveals that they had not imagined the Red Army will mobilize troops from the vast Soviet territories
Incorrect.
This answer choice is grammatically incorrect. The sentence uses the Present Simple tense reveals to describe an event that occurred at a specific moment in the past (the Battle of Moscow in December 1941).
In addition, the second part of the sentence is anchored in the past by the Past Perfect verb had not imagined. By default, this sentence should remain in the Past tense. The verb will mobilize, however, is in the Future tense.
Remember our rule: Once in the Past, always in the Past.B. reveals it hadn't been imagined that the Red Army would mobilize troops from the vast Soviet territories
Incorrect.
While this answer choice corrects one of the original tense mistake, it repeats the other. Using the Present tense reveals to describe an event that occurred at a specific moment in the past (the Battle of Moscow in December 1941) is grammatically incorrect.
In addition this answer choice is stylistically flawed. Changing they didn't imagine to it hadn't been imagined makes the sentence ambiguous and confusing, as it is not clear who or what it refers to.C. revealed that they hadn't imagined the Red Army will mobilize troops from the vast territories of the Soviet Union
Incorrect.
While this answer choice corrects one of the original tense mistakes, it repeats the other.
The second part of the sentence is anchored in the past by the Past Perfect verb hadn't imagined. By default, this sentence should remain in the Past tense. The verb will mobilize, however, is in the Future tense.D. revealed that they did not imagine that the Red Army would mobilize troops from the Soviet Union's vast territory
Incorrect.
While this answer choice corrects both original tense mistakes, it is grammatically incorrect: it uses the Past Simple tense (did not imagine) to describe an action that was completed before another action in the past.
Since the Axis power's failure to imagine that the Soviet military would mobilize occurred before the Battle of Moscow revealed this failure, the Past Perfect tense should be used to describe the earlier action.E. revealed that they had not imagined the Red Army would mobilize troops from the vast Soviet territories
This answer choice corrects both tense mistakes in the original question. It changes reveals in the Present to revealed in the Past Simple (to describe an action that occurred at a specific time in the past - December '41). It also changes will in the Future to would in the Future Past, as required by the verb had not imagined, which anchors the action in the past.
Note also that like the original sentence, this answer choice correctly uses the Past Perfect to describe an action that occurred before another action in the Past, as the Axis power's failure to imagine that the Soviet military would mobilize occurred before the Battle of Moscow revealed this failure.