What is the name of a structure that usually contains "how" or "what" and inverted word order but is not a question?
Example: "Our goal is to investigate until we know how it was done".
English Language Learners Stack Exchange is a question and answer site for speakers of other languages learning English. It only takes a minute to sign up.Sign up to join this community
In the sentence "Our goal is to investigate until we know how it was done" the bold part is a free relative clause (nominal relative clause, a fused relative construction, an independent relative clause, or (in traditional grammar) a noun clause); a type of relative clause (that is, a word group beginning with a wh-word) that contains the antecedent within itself.
A free relative can refer to people or things, and it can function as a subject, a complement, or an object.