My friend didn't see the dentist four days ago
Did your friend see the dentist four days ago
Who saw the dentist four days ago?
Who did your friend see four days ago?
When did your friend see the dentist?
)
My friend didn't see the dentist four days ago
Did your friend see the dentist four days ago
Who saw the dentist four days ago?
Who did your friend see four days ago?
When did your friend see the dentist?
)