"What the exact mix of experience and natural talent [was] that made Austen the brilliant [writer] she was may never be [remove un]known."
As for why it is incorrect... because it is confusing, because there is nothing for brilliant to modify, and because "may never be unknown" is opposite to the contextual meaning of the sentence.
The added text in brackets fixes the grammar, but the sentence is still rather awkward. I'd reconstruct it this way:
What the exact mix of experience and natural talent was that made Austen a brilliant writer may never be known.
Or, more simply:
The exact mix of experience and natural talent that made Austen a brilliant writer may never be known.
Or even:
We may never know what combination of experience and talent made Austen great.
It was incorrect It is incorrect That is incorrect That was incorrect
I would of liked to see that.The "of" should be have or 've
The sentence (not sentance) is grammatically correct
incorrect
Der Junge ist rothaarig is grammatically correct.
You're question is incorrect
The sentence "I will go to the store yesterday to buy groceries" has mixed verb tenses and is incorrect.
It was incorrect It is incorrect That is incorrect That was incorrect
I would of liked to see that.The "of" should be have or 've
The sentence is grammatically incorrect. It should be structured as "Taking a psychology test," with the subject preceding the action.
no
The diamond is brilliant. (shiny) The idea was brilliant. (good)She was a brilliant person. (smart)The speaker had brilliant sound quality. (clear)
The sentence (not sentance) is grammatically correct
incorrect
yes,it is incorrect to start a sentence with ''and'' as it is a word to combine wo sentences together, not start a sentence
One thing is sure. It wasn't written by Austen. The meaning is detectable, but the sentence is awkward. At the end, I think you mean to say "...may never be known." The word "what" is superfluous. It forces you to make the complete subject more complicated than necessary. It leads the ear to that ubiquitous and unnerving "what it is, is..." clash. You are compelled to say something like: "What the exact mix of experience and natural talent [is or was] that made Austen the brilliant writer she was..." Just leave out the "what". This is better, but not particularly good: "The exact mix of experience and natural talent that made Austen the brilliant writer she was may never be known" Simple answer: It is incorrect because it lacks a main verb. The verb "was" needs to be inserted between "talent" and "that."
The second sentence is grammatically incorrect. The correct sentence should be: I want to visit Hawaii.