If the second half of the sentence is not completing the idiom not X but Y, then it should offer a contrast that is parallel with the subject and main verb of the first clause (paleontologist Stephen Jay Gould has argued). For example:GMATMadeEasy wrote:@GMATGURUNY :
Q1> I ignore for the moment that due to is incorrect here . Can we really eliminate A and B for those reasons ? WHy ?The correct idioms are either are not X but Y or are not X but are Y. Eliminate A and B.
"But that they are" and but they are" simple take subject of the previous clause and ,in my opinion, can we written this way .
Q2 > I would like to know the usage of "that" in "But that they are" ? Why ? I understand that parallelism requires "that " to be used if second clause is independent (I said that clause1 and that clause2), but , if second clause is treated as independent, an it take the subject of the first clase as is the case here ? in "but that they are " and in "but they are" both "they" reer to the subject of the previous clasue.
Paleontologist Stephen Jay Gould has argued that X...but others claim that Y...
Does this help?

















