So in my N4 textbook, I have the following explanation for a grammatical construct:
Noun + なら:
Use "〜なら" when you say that options are no good, but "〜" is possible, okay or not a problem.
The examples don't make a lot of sense, so I go and google なら. All I can find is stuff about how なら is a particle used to express conditionals, i.e. it's one of the ways of saying what 'if' says in English. This is a meaning of the なら particle that I'm familiar with. I can't find anything about any other meanings of なら.
Can someone explain what my book is on about? Is this related to なら's 'if' meaning, or is it an entirely different word/meaning completely?
The book examples are:
1) 日曜日なら時間が取れるから、いっしょに買い物にいこうよ。
I think this is supposed to mean - I have time on Sunday, let's go shopping together. The なら supposedly implying that days other than Sunday are no good.
2) A: 今度のパーティーでつうやくをしてもらえませんか。
B: すみません。手紙のほんやくならできますが、つうやくはちょっと...。
So now it's lost me, I have no idea what this is supposed to mean, and what なら is doing here.