I'm in 7.29 working through the second level of Greek to GCSE, and I came across this:
περὶ δὲ τοῦ Χαιρεφῶντες ἠκούσατε πάντες. οὗτος γὰρ ὁ ἐμὸς φίλος ἐκ νέου ἦν.
It seems to me that ὁ ἐμὸς φίλος is supposed to be a predicate nominative and οὗτος is the subject: "For this (man) was my friend since youth."
Question: Why is the PN definite? Shouldn't we expect it to be indefinite and οὗτος ὁ ...