‘it feels great to be ~ ’

Hello, everyone,

1) “It feels great to be on this ship.” - an excerpt from our local textbook;

G: Wow, it feels great to be on this ship, Dad.

M: I feel the same, Sora. Here are our seats, 20A and 20B.

G: Yeah. Do you mind if I take the window seat? I like to see the view outside.

2) “It felt strange to be back in my old school.”

3) “It felt as though he had run a marathon.”

* 2) and 3) above ; excerpts from https://www.oxfordlearnersdictionaries.com/definition/american_english/feel_1

“linking verb (not used in the progressive tenses) to give you a particular feeling or impression (+ adj.)”

By the way I have following inquiries;

1. If the three sentences have the same construction in common?

2. How to parse the grammatical functions of ‘it’ and ‘to infinitive/as though clause’ - that is, the construction of ‘preparatory it + exrtraposed subject’ or the one of ‘empty subject it + complement clause’?

I personally think the patterns of three sentences above as follows;

- 1), 2) above; empty subject ‘it’ + linking verb + ‘to infinitive’ complementing the preceding adjective – ‘great, strange’ - with similar meaning to “it feels great when(because) I am on this ship.”

- 3) above; empty subject ‘it’ + linking verb + ‘as though clause’ complementing the preceding verb ‘felt’.

I would appreciate it, if you kindly share opinions.