Questions without auxiliary verbs

Look at these two questions:

Question word	Auxiliary	Subject	Verb
Who	do	you	love?

Question word	verb	object
Who	loves	you?

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.

Other examples:

Question word	verb	object
Who	wrote	Romeo and Juliet?
Who	won	the 2006 World Cup?
Which player	fouled	Ronaldo?
What	happened?

Related pages:

English Grammar Reference: Questions with auxiliary verbs