Questions without auxiliary verbs
Look at these two questions:
The first question is a normal question and uses the form which we almost always use for a question:
question word + auxiliary + subject + verb
In the second question, the question word is the subject. When the question word is the subject there is no auxiliary verb and the verb agrees with the subject.
|Who||wrote||Romeo and Juliet?|
|Who||won||the 2006 World Cup?|
English Grammar Reference: Questions with auxiliary verbs