Clauses that function as nouns: what you said, that she left, whether it works
That/What/Whether/If + subject + verb (statement word order)
That/What + subject + don't/doesn't + verb
Do you know + noun clause?
💡 That can often be omitted: I think (that) he's right. Use whether/if for yes/no embedded questions.
✓I believe that she is honest.
✗I believe that is she honest.
Statement word order in noun clause.
✓What he wants is unclear.
✗What does he want is unclear.
No inversion in noun clause.
✓I don't know whether he's coming.
✗I don't know whether is he coming.
Statement order after whether.