I am supposed to state how the italicized noun clause is used, but I'm not sure how to tell the difference.. can anyone help?

1. [What I wanted to do] was to finish my work.

S <---- i was thinking subject?
OP
PN
or DO?

2. The valedictory prize will be awarded to [whoever has the highest academic rating.]

S
OP
PN
or DO?

3. The chairman heard [what was said about the program.]

S
OP
PN
or DO?

4. A good night's sleep is [what I need most.]

S
OP
PN
or DO?

I honestly have no idea.. ugh, english is my worst subject.. can anyone help & explain? thank youu!

2 answers

1. Correct.

2. What about the word, "to?"

3. Correct.

4. What are clauses that follow linking verbs?
^lolwut