1."for" in Q1means 为 or 为了,both True. But it's not suitable here to use 给 though there's no mistake in grammer,the reason is that the object of 给 is people or something alive better.And 为 or 为了are the same with dead or alive thing. 2.As I said above,you can use 为or给here,pefect work!

"I cooked for you" can also translated into "我为你做饭了". Maybe 给 is more specific and 为了 is more abstract and wide ranged in my opinion. Eg: I did this all for you. 我做这些都是为了你 I did cleaning for you. 我给你打扫卫生了

I wouldnt say that “给” and “为” They are not interchangeable in case 2. 给 = to give, 为 = do for I cooked for you- 我为你做饭了 I made you a meal 我给你做饭了 in this case you cannot replace "给" with other characters since normally if you changed vt, you changed the meaning.

Hello Luca~I am chinese,maybe i can give some ideas for you^^ In chinese,there are many prepositions,such as 为，向，给，朝，到，往，在……etc,and they are divided according to Time,purpose,reasons and so on,just like English does.The key is,you need to distinguish the language environment this sentence belongs to,and then choose the best word to describe.^^hope it's hopeful~

I can't fully understand how to express the "for" preposition in chinese language. I'll just write down 2 examples, i'd like you to help me translating them (I'll also try to translate by myself): 1- I'm now studying for tomorrow's exam 现在我为明天的考试在学习/我正在复习明天要考试的科目 here I used 为, is it correct? could i use 给 too? 为了明天的考试，我正在学习：语法上对 但听着不口语化 this is a "bonus" sentence, does it sound better this way with 为了? 2- I cooked for you 我给你做饭了 here i used 给 just because it "sounds" more colloquial. So probably my question is more about 为 vs 给 in "for" meaning. Any other example is appreciated. I'm not native english speaker, i'm sorry for possible errors... Thank you