The use of “t-on”

Question

I don’t understand the purpose of “t” here as the verb is not reflexive. All these are equivalent but I’m at a loss of the use of “t-on” . What lesson would help with this?On ouvre les cadeaux quand ?Quand est-ce qu'on ouvre les cadeaux ?Quand ouvre-t-on les cadeaux ?Quand on ouvre les cadeaux ?

Jim Jones · Accepted Answer

Bonjour David,
https://french.kwiziq.com/revision/glossary/contraction/l-elision-elision
I suspect that the link above will help.
I see the issue being that of "ouvre-t-on"; otherwise, there would be a liaison issue between e (ouvre) and o (on), the t avoids this as an aid to the flow of the text overall.
(Try saying the text to yourself without "t")
I hope this helps.
Bonne journée
Jim

Cécile Janty-Davies · Answer

Bonjour David, 
Just to add to Jim's answer, please take a look at Maarten's answer to a similar question -
https://french.kwiziq.com/questions/view/inserting-t-after-verbs-ending-in-a-t-sound
 
Hope it helps!