I'm very confused about the たら conjunctive particle with questions. It seems that the general structure is XらY, where X is some kind of condition in the past tense and Y is something that happens after the condition is met. For example:
会議が終わったら、 電話しますね
Here, X, the condition, is "when the meeting ends", and Y is 電話しますね, "I'll call you".
All examples I found on my grammar book follows this template rather nicely, however, when trying to read I found this:
友達に何を贈ったらいいですか。
Here, Y is probably "is good?"/"is desirable?", but X, 友達に何を贈った is a question? how can a question be a condition?
Another similar one is:
何処で日本円に両替したらいいですか
I saw that the translation is something like "Where should I exchange money into Japanese yen?", but I don't see how the "conditional" logic of たら works here. Like the example before this one, the condition is 何処で日本円に両替した, a question too? How can that work?
EDIT: I cannot comment, so I'll update this question:
A phrase like:
一緒にお出かけしたらどう？
I can understand fine. In this case, the "accomplished situation" would be "we go out together" and after comes a question if it's fine.
But when it's something like:
友達に何を贈ったらいいですか。
The first part, 友達に何を贈った, I would interpret like "what did I give to my friend". But it's very strange, how can a "accomplished situation" be a question?! If I assume that 何 can mean "something" in this case, then it could make sense. But even then the "accomplished situation" would be "gave my friend something", putting everything together I would get "Is it okay if I gave my friend something", which is still wrong. What is binding the question to what is being given instead of the act of giving itself?
I think I might have a problem understanding pronouns (like 何, 誰), because when I saw this example on the comments:
あなたは誰が書いた本を読んだんですか？
I assumed that 誰が書いた meant "someone wrote", and this is like an "adjectival sentence" for 本, so the translation would be something like "Did you read the book written by someone". But it seems the intention was to say "Who wrote the book you read?". What is "binding" the question to the author of the book instead of the act of reading?
