Definitions for "Tenses"
These are three main tenses: the Present, Past and Future. If a writer suddenly switches tenses, he is doing so for a particular reason. If, for example, he changes from the past to the present, he may be trying to convey a sense of immediacy, of the event happening NOW. There are THREE past tenses in English: the Simple Past to indicate something that has happened in the immediate past, the Continuous Past to show an incomplete action and the Past Pefect where you want to indicate an event that is over and done with in the more distant past. For example: Yesterday he went to the shops to gaze at the array of new bicycles. (Simple) He was examining the elaborate gear system when the salesman intervened. (Continuous) The previous week he had indicated to his parents that he would like a new bicycle for Christmas. (Past Perfect)