“Je ne devrais pas avoir à passer derrière toi !”

Question

Hi, what is the purpose of “avoir” in “Je ne devrais pas avoir à passer derrière toi !”? The string of verbs seems odd. What meaning, for instance, would be lost if it were just “Je ne devrais pas à passer derrière toi !”?

Accepted Answer

Brian, devoir is a ‘semi-auxiliary’ verb, and except in one context, will always be followed by an infinitive verb. You cannot use devoir on its own here - it makes no sense in French. 
In the construct, it fills the role that the modal ‘should’ does in English, and the overall structure is not that different - 
‘ne devrais pas’  - shouldn’t/ should not
 ‘avoir à’ - have to
‘passer derrière toi’ ‘ - go/walk/pass behind you.
The exception is devoir-noun - in which devoir has a different meaning, “owe something”. 
 https://www.lawlessfrench.com/grammar/devoir-lesson/
 https://www.wordreference.com/fren/avoir%20à%20faire
 https://progress.lawlessfrench.com/my-languages/french/glossary/111

Answer

Hi Maarten, thanks for breaking that down. And great links too!