"the thing that he did". Thus the noun phrase the thing and the relative pronoun that are 'fused' into what; and the resulting relative construction "What he did" functions as the subject of the verb was. Free relative constructions are inherently restrictive. English has a number of "fusible" relative pronouns that initiate relative constructions, including what, whatever and whoever. But these pronouns introduce other clauses as well; what can introduce interrogative content clauses ("I do not know what he did") and both whatever and whoever can introduce adverbials ("Whatever he did, he does not deserve this"). See -ever. Nonfinite relative clauses Some non-finite clauses, including infinitive and participial clauses, may also function as relative clauses. These include: infinitive clauses containing an 'explicit' relative pronoun (argument)generally, but not always, fronted with a prepositionthat takes an antecedent to that 'explicit' argument: She is a woman whom to beat; He is the man on whom to rely. (The infinitive verbs are 'to beat' and 'to rely'; the antecedents are 'woman' and 'man', respectively.) infinitive clauses presenting an 'implied' (and unvoiced) relative pronoun, or zero object argument, that takes an antecedent to that 'implied' argument: She is a woman to beat Ø; He is the man to rely on Ø. infinitive clauses modifying the subject of the infinitive verb: She is the person to save the company. present participle clauses having an unvoiced zero subject argument that takes an antecedent to the argument: The man Ø sitting on the bank was fishing. (These clauses are the least likely to be recognized as relative clauses.) past participle clauses having an unvoiced zero object argument that takes an antecedent to the argument: The body found Ø here yesterday has now been identified. (This is the "reduced object passive relative clause"; see . For further examples see . Adverbials Some adverbial clauses can function as relative clauses, including: clauses modifying a noun, with the adverb explicit or implied (and normally replaceable by a relative clause): Here's the place I live, that is, Here's the place [where] I live ("Here's the place in which I live"). Or: This is the reason we did it, that is, This is the reason [why] we did it ("This is the reason for which we did it"). clauses functioning analogously to free relative clauses, but in an adverbial role: I won't hide where you hide. Or: I'll do it how you do