"Ποιος έχει το όργανο;"
Μετάφραση:Who has the instrument?
Is it not wrong to ask a question with only "has"? To me it looks right if you set only a form of be for question forming, but in case of "to have" there has to be either a "got" or a form of "do".
Do you have the instrument?
Who does have the instrument?
Have you got a brother?
- Has he got a car?
Questions with "Who" are a special case, because you are missing the subject.
For example, we know that simple past questions are formed with "did", but when you ask with who, it's correct to say:
"Who ate my food?" instead of "Who did eat my food?", which is actually wrong.
The same with the verb have/has, it's correct to say "Who has the instrument?" instead of "Who does have the instrument?".