Subject

EnglishGirl What is the subect in this sentence:Who is that man with your wife?Thank you

Who.

Anybody?

Thank you. Then, what would be the function of that man with your wife?

EnglishGirlThank you. Then, what would be the function of that man with your wife?

A complement.

I thought so but my colleagues thought that that man with your wife was the subject. Could you just give me the brief explanation for this.

EnglishGirlI thought so but my colleagues thought that that man with your wife was the subject. Could you just give me the brief explanation for this.

I take the question, Who is that man with your wife?, as one expressed in the affirmative, hence my understanding of that. But if you consider the verb is (in that question) as an interrogat

Then, what is the function of Who? This is really confusing...

EnglishGirlThen, what is the function of Who? This is really confusing...

The interrogative word (pronoun) if you take the verb is as an interrogative one.

The subject in the sentence is "man". The words "that" and "with your wife" are modifiers that describe the subject. "that" functioning as adjective and "with your wife" functioning as an adjectival prepositional phrase.

The sentence is an interrogative sentence (a question) and if we rearrange it into a declarative sentence (a statement) it would look like this:

That man wit

I see your point. But, anyway, I would go that that man with your wife is the subject on the sentencial level.