Abstract : This paper examines the tenses used in a subclause that refers to a situation that is anterior to a main clause situation referred to with a past tense.More in particular, it examines in what contexts a past perfect is required and to what extent it is interchangeable with a past tense without the temporal relation of anteriority being blurred. A range of factors are identified that constrain the use of a past tense to refer to an anterior situation in such contexts.