Inwh-questions, the word order changes from subject + (auxiliary/modal) + main verb towh-word + auxiliary/modal verb + subject + main verb:
What was she eating?
Not:What she was eating?
Inyes-noquestions, the word order changes from subject + (auxiliary verb) + main verb to auxiliary verb + subject + main verb:
Were you talking to Johnny?
Did you tell Rosa about what happened?
If there is no auxiliary verb in the affirmative, we usedobefore the subject:
Doyou agree?
Not:Are you agree?
Whatdoesart mean?
Not:What art means?orWhat means art?
We can only use auxiliary and modal verbs, not main verbs, before the subject:
Wherewasthe painting bought?
Not:Where was bought the painting?
Howisthe fish cooked?
Not:How is cooked the fish?
We usewhat, notwhich, to ask about specific information from a general range of possible answers:
What’s the name of the man who owns your company?
Not:Which is the name of the man who owns your company?
See also:
Questions:yes-noquestions (Are you feeling cold?)
Questions:wh-questions
Questions: interrogative pronouns (what,who)