predicate nominative or subject complement
Hi!

I am studying noun clauses (aka that-clauses aka nominal clauses) right now. I thought I've understood something. It appears I didn't.
Take a look at this sentence.
A new computer is what Matthew needs. [predicate nominative identifying the subject computer]

I thought (and italki user Michael Chambers also said) that the noun clause in this sentence is a subject complement. I am confused.

Thank you for your explanation!

Question

predicate nominative or subject complement
Hi!

I am studying noun clauses (aka that-clauses aka nominal clauses) right now. I thought I've understood something. It appears I didn't.
Take a look at this sentence.
A new computer is what Matthew needs. [predicate nominative identifying the subject computer]

I thought (and italki user Michael Chambers also said) that the noun clause in this sentence is a subject complement. I am confused.

Thank you for your explanation!

Answer

Is it just a terminology issue?

https://www.thoughtco.com/subject-complement-grammar-1692001

A subject complement is a word or phrase (usually an adjective phrase, noun phrase, or pronoun) that follows a linking verb and describes or renames the subject of the sentence. Also called a subjective complement.

In traditional grammar, a subject complement is usually identified as either a predicate nominative or a predicate adjective.

Answer

"what Michael needs" is the noun clause, yes and it functons as predicate nominative identifying the subject computer. And my question is how should I know when noun clause is predicate nominative and when it is a subject complement.

Answer

I'm confused too! (by your question).  Not sure what part of the sentence you're asking about.

"what Michael needs" is the noun clause
"Whatever you want to do" is fine with me.  "whatever you want to do" is the noun clause.

will this help?
https://www.k12reader.com/term/noun-clause/