Look at structures a and b. Find three more examples of structure b in the Memory quiz
on page 6. When do we not use did in a
question?
a question word + did + subject + main verb
Who did you visit? I visited my aunt.
Which did you get, the bus or the train? I got the bus.
(The question word refers to the object.)
b question word + main verb
Who visited you? My grandfather visited me.
Which cost more? The train cost more.
(The question word refers to the subject.)