The sentence is incomplete in several ways; either (A) the subject and verb are missing or, (B) the verb and the object are missing.
Also, 'a lot of' infers that the noun 'question' should be plural, 'a lot of difficult questions'. Even the relative clause is incomplete; clauses require a verb (researched and answered are used as examples).
(A) Adding a subject and a verb (is) with the object student and 'who has successfully...' as the relative clause relating to the object.
Levi is a student who has successfullyresearched a lot of difficult questions.
She is a student who has successfully answered a lot of difficult questions.
(B) The subject is now 'student' and the relative clause 'who has successfully...' relates to the subject; the verbs 'will receive' and 'will pass' are now the verbs and 'grade' and 'course' are now the objects of the verbs.
A student who has successfully researcheda lot of difficult questions will receive a higher grade.
A student who has successfully answereda lot of difficult questions will pass the course.
There is no sentence in the question on which to base an opinion.
So you think that's a difficult question, do you?
Dogs are better then human? what ia the correct sentence
If it's used as a question, yes. If not, then it is a correct phrase but not a complete sentence.
The correct sentence is the following: "What were you doing from before?"
Yes. That is a correct sentence, or at least a correctly formed sentence*. But there is no content that can be judged as right or wrong. (*It is an interrogative sentence, one that asks a question.)
In casual writing you might be able to replace a question mark with a period, especially in dialog to indicate intonation, but usually the sentence structure of questions is different, so that a period will not be correct. For example, "Where did you go?" is correct as a question, but "Where did you go." is not correct.
Yes. She found is correct, Bob and Bill found is correct so She, Bob and Bill found is correct.
The grammar in the question is correct.
No, it is not. The "question word," why, should be at the beginning of the sentence. Why was she promoted?
No, the correct sentence would be "Who is the singing woman?" by adding a question mark at the end. It is asking for the identity of a woman who is singing.
this is a question so at the same point this is a sentence