"It's an honour to see you."
Is it dummy "it" and is "to see you" a real subject? "To see you is an honour."
Or does "see you" function as an adverb of 'reason'? It's an honour because I see you.
"It's an honour to see you."
Is it dummy "it" and is "to see you" a real subject? "To see you is an honour."
Or does "see you" function as an adverb of 'reason'? It's an honour because I see you.
It's an honour to see you.
Your example is called an Extraposition construction -- one consisting of "it" as subject and the postverbal subordinate clause ("to see you") in extraposed position.
The basic (non-extraposed) equivalent has "to see you" as subject:
To see you is an honour.
Note that in Extraposition the "it" is a dummy element serving the syntactic purpose of filling the subject position; the extraposed element doesn’t give the meaning (reference) of "it" but serves simply as a semantic argument of the verb phrase.