Noun clauses beginning with a question word (UUEG 12-2)
What she said surprised me. "What she said" is the subject of the sentence. A noun clause subject takes a singular verb.
Relatives (4): what — What does not refer to a noun that comes before it. It acts as noun + relative pronoun together, and means 'the thing(s) which'. Clauses beginning with what can act as subjects objects, or complements after be.(PEU 497)
Cleft sentences (1): What I need is a holiday (PEU 130)
We can emphasize particular words and expressions by putting everything into a kind of relative clause except the words we want to emphasize : this makes the stand out. These structures are called 'cleft sentences' ('divided'). They are useful in writing (because we cannot use intonation for emphasis in written language) , but they are also common in speech." — Swan
What I need is some help. I need some help.
"A what-clause is normally considered to be singular; if it begins a cleft sentence it is followed by is/ was/ But a plural verb is sometimes possible before a plural noun in an informal style."(PEU 130.1)
The fused relative construction (CaGEL 12 §6)
The fused relative is not analyzed as a clause. Instead, it is a NP [noun phrase] or PP [prepositional phrase].
- We cannot abandon that which we hold dear. [antecedent + clause]
- We cannot abandon what we hold dear. [fused relative]
a) Verbs agree with the fused relatives:
- What advice he gives is valuable.
- %What suggestions he gives is valuable.
- What suggestions he gives are valuable.
b) Subject-auxiliary inversion
- What he suggests is acceptable.
- Is what he suggests is acceptable.
(S-V inversion is a feature of NPs but not a feature of clauses. Compare: That he suggests a change is acceptable. *Is that he suggests a change unacceptable?) (12 §6.1b)
c) No extraposition
- What he suggests is questionable.
- *It is questionable what he suggests.
(Like ordinary NPs, fused relatives do not occur in the extraposition constructions.)
d) No fronting of prepositions
- What he refers to is questionable.
- *To what he refers is questionable.
(The preposition is not integrated into the construction)
e) Functional range of NPs (CaGEL 12 §6.1e)
- What he said was funny. [subject]
- They say what they want. [direct object]
- They tell whoever they see the news. [indirect object]
- They made him what he is. [predicative comp]
- They were anxious about what they did. [object of prep]
f) See (CaGEL 12 §6.)