Fill in the blanks in the order you hear them. "... did you hear that" is an attributive clause? What are relative words?

Can you guarantee its correctness?

Take a good look, I always feel that what you hear should have no theme.

I can tell you that I think this sentence you gave is wrong.

As a relative pronoun, that can be used in object clauses, subject clauses, predicative clauses, attributive clauses and appositive clauses. When that leads the object clause, it does not constitute a component and can be omitted; When guiding the subject clause, don't be a component and you can't omit it; When guiding advertising language clauses, do not make components and cannot omit them; When guiding an attributive clause, it can be used as a subject or an object, and it can be omitted when it is used as an object; When guiding appositive clauses, don't make components and don't omit them.

If you think "you hear them" is a clause, then this clause is not lacking in components. At the same time, this sentence cannot modify, explain or explain the previous nouns.

Therefore, I think this sentence itself is wrong.