Something can happen now (present), tomorrow (future) or yesterday (past). Verb tenses (= глаголска времена) show the time of an action.
In English, two tenses are used to talk about the present (present simple and continuous) and six to talk about the past (past simple and continuous, present perfect simple and continuous, past perfect simple and continuous). Future can be expressed in different ways, including the present tenses.
Each of the tenses has four forms: simple, continuous, perfect simple and perfect continuous. The simple tenses show that something is permanent, happens regularly or is completed. The continuous tenses talk about ongoing actions. The perfect tenses link the present to the past or the future.
Watch this video for a brief view on English tenses:
Try the exercises here.