I don't understand the role of "な" when used before "のに" as in these two sentences (with given translations):
He noticed that there was snow outside only after he woke up in the morning.
Although Sunday is precious (to me), I worked (all day long).
I'm similarly confused by the なので pattern, but I assume the principle is the same there. My best guesses so far are that:
- There's some relation to な-adjectives, but I don't see how 雪 or 日曜日 would be acting as adjectives here.
- The な has essentially the same role as だ (i.e. a "copula"?), but you can't use だ in the middle of a sentence like that.