Good morning, Satty.
(1) Here is a somewhat similar sentence from one of my grammar books:
They seemed to be drifting about.
(a) The authors of the book analyze it this way:
(i) They = subject.
(ii) seemed = linking verb.
(iii) to be drifting about = infinitive phrase acting as a subjective complement (refers to "they").
Have a nice day!
- For Teachers