This asserts that, while he was in Madrid, there were no occasions on which the Pedro dined out. This does not assert there were no occasions on which the Pedro dined out when he was in Madrid. Instead, it says that, at the time of his visit to Madrid, Pedro was not a frequenter of restaurants, i.e. the sequence no cenaba fuera is dispositional . The incompatibility between the imperfect and temporal quantification affects all classes of predicate. These are best regarded as forming a single dispositional term with rest of the verb phrase.
Dispositional predicates are like stative predicates in that they have the subinterval property.
Items like nunca sometimes function as frequency adverbials and sometimes as temporal quantifiers. Given that temporal quantification calls for the preterite while dispositional sentences usually call for the imperfect, it is easy to see how aspect selection distinguishes between the frequency and quantificational meanings of words like nunca . Durational adverbials such as durante diez minutos specify the amount of time occupied by a situation. They are said to be downward-entailing , which means that if a situation holds for an interval I that is determined by a durational adverbial, the situation holds also for any subintervals of I . Depending on the aspectual class of the relevant predicate, such phrases are compatible with clauses in either the preterite or the imperfect, although different temporal relations arise in the two cases.