what had been going on ...
past event
translation
Tammy attendait Tex depuis une heure ...
... quand il est entré.
Tammy had been waiting for Tex for an hour ... when he came in.
Tammy souhaitait avoir une discussion sérieuse depuis lundi ...
... quand enfin le moment s'est présenté.
Tammy had been wanting to have a serious discussion since Monday ... when at last the opportunity presented itself.