Sentence Correction

Though the Pythagorean theorem is attributed to Pythagoras, a mathematician and philosopher who lived in the 6th century BC, the first proof had not been completed before the year 300 BC, when it appeared in Euclid's Elements.

A. the first proof had not been completed before the year
B. it had not been proven to be true before the year
C. the first proof of the theorem was not completed prior to
D. the first proof was not completed until
E. it was not proven to be true prior to

B

A, C, E are out as they do not have the pronoun "it" to refer back to the subject "the p theorem".

B better than E as it uses a past perfect to denote that the event "not proven" happened before 300bc , the year it appeared in E's theorem.

Is it C ?

A and B have the year 300 BC - redundancy error

E is wrong- "it " wrong

D uses until - not sure if this correct- different from what the original sentence seems to imply.

Is it D?

IMO D

until..... very precise word

we don't require a past participle here..

OA : D

I searched this question in almost all the forum and found that "prior to"" can only be used to refer to an event(like prior to establishment of something) so C and E are wrong. A and B use year 300 BC which is redundant....so we are left with D..

Thank You everone for your responses.

gmat620 wrote:Though the Pythagorean theorem is attributed to Pythagoras, a mathematician and philosopher who lived in the 6th century BC, the first proof had not been completed before the year 300 BC, when it appeared in Euclid's Elements.

A. the first proof had not been completed before the year
B. it had not been proven to be true before the year
C. the first proof of the theorem was not completed prior to
D. the first proof was not completed until
E. it was not proven to be true prior to

since this sentence talks about sequence of event happening....past perfect tense should be used..........samen is used in choice A

Please explain......

I was confused between A and D.

I second ankit.
There are 2 events happening at 2 diff times in past

IC1 - Attributed to P

IC2 -
Event 1 - First proof not completed until 300 BC
Event 2 - Appeared in euclid elements.

I am not sure if past perfect be applied here.

IMO D

Was not completed, explains the sequence of events.

ronniecoleman wrote: we don't require a past participle here..

Would you kindly explain more mate? I thought we need "had" here because "not being completed" is before "appearing in Elements".

When we have two events in the past, the older one would require "had".

Arsene Lupin wrote:

ronniecoleman wrote: we don't require a past participle here..

Would you kindly explain more mate? I thought we need "had" here because "not being completed" is before "appearing in Elements".

When we have two events in the past, the older one would require "had".

I don't think 'had not been' is correct here, since we Pythagoras lived before the proof was completed. It was completed afterwards, so 'had not been' would refer to a time before Pythagoras.