I still can't get my head around how I am supposed to place the counters.
According to my textbook (which of course may have oversimplified some things), there are two possibilities: counter + の + noun OR particle + counter + verb.
But what if there's no verb (only the optional copula です)? I'm specifically interested in the construction te-verb + もいい(です).
Of course most of the time I can just attach it to the noun
何枚の写真を撮ってもいいですか - How many photos am I allowed to take?
五枚だけの写真を撮ってもいいです - You're only allowed to take five photos.
but what if I can't, since there are no nouns?
歌っても一回いいです (?) - I'm allowed to sing [it] once.
Is the above sentence correct? Should I treat いい as a verb (similarly to 好き)? If you know any resource explaining this in depth, linking it would be appreciated.
BTW Feel free to correct my sentences. I've been only learning Japanese for 2 months, so I expect there to be mistakes.