The imperfect tense is used to talk about what someone used to do, what used to happen or what something used to be like. The imperfect tense is used to talk about what used to happen regularly and to ...
You use the perfect tense when, in English, you would say that something has happened. So, if you wanted to say: ‘You have been to the hairdresser,' 'she has eaten all the biscuits’ or anything else ...