Why is the "O" necessary?
Que = that, o que / o quê = what
Nem sempre veja:
What book do you have? Que livro você tem? Correct
O que livro você tem? Incorrect
Sure. With a context, words may have other meanings and usages.
,,O que você tem na sua mala" - is it wrong ,,sua"? LOL? The answer shows that correct version should be ,,tua"... As far as I know, ,,tua" etc appear only in the European portuguese.. ?
No, not only in European portuguese..... i have plenty of books using teu/tua, but it is old, not modern, but still correct
which is the difference between "o quê" and "qual"? i thought "qual" means "which' but at times it is translated "what" and it really got me confused...
Why not "O que é que tem na mala"?
I put it as "O que é que você tem na mala?" and it was marked correct, so I think all that you were missing was the "você".