progressive aspect

progressive aspect (samtidsform): a verb category with two principal meaning components: (limited) duration and (possible) incompletion. In English the progressive aspect is realized by the grammatical auxiliary be followed by an-ing participle. The progressive aspect usually does not occur with stative verbs, as these verbs denote permanent situations (which does not fit with the meaning of limited duration). Combined with the present tense, the progressive aspect denotes ongoingness and incompletion (E.g. I am reading about English grammar). Combined with the past tense, the progressive aspect denotes (limited) duration in the past and possible incompletion.(E.g. I was reading the paper last night -- the speaker may or may not have finished reading; the emphasis is on the activity of reading.) The past progressive is often used for background activities which are interrupted by another event, e.g. I was having a bath when the telephone rang. When the progressive aspect combines with the perfective aspect, the meaning is that an activity stretched from the past up to a specified point of time (or possibly even beyond that). E.g. I've been cleaning the windows (that's why there are no curtains at the moment). They had been studying hard for their exam.