i am confused. there is another lesson that uses deber in perfect tense and deber in present + haber to indicate assumption that something must have happened that is expressed by the main verb as infinitive or past participle. This lesson seems to be speaking of the same thing until the last part that says
Eso debe de haber caducado hace tiempo
That must have expired some time agoI am confused by this 2 very similar lessons. may you point out the differences to me?
how do I use such structure to say something must had been done as in an assumption in the past?
