We use the present perfectThe aspect expressing completion. E.g.: He’s finished university. continuousThe aspect expressing duration, formed with be + verb-ing. E.g.: What are you doing? tenseA grammatical category that is marked by verb inflection. To express when an event or action happens in time or when a state exists, we use tenses. for actionA general term expressing that somebody or something does somethings which started in the past and are still in progressAn action is in progress when it is happening. E.g.: When I arrived he was surfing. ("he was surfing") in the present or have just finished.

I've been waiting for you for ages.
He has been living in that flat since last January.

The prepositions for and since are often used with the present perfectThe aspect expressing completion. E.g.: He’s finished university. tenseA grammatical category that is marked by verb inflection. To express when an event or action happens in time or when a state exists, we use tenses.. For is used with an incomplete period of timeA period of time that includes the time of speaking. E.g.: I have known him for two years. ("for two years"), while since with a point of timeA particular moment in time. E.g.: She came home at six. ("six") I was born in 1980. ("1980") .

The past simple is used for actionA general term expressing that somebody or something does somethings that took place over a complete period of timeA period of time that has finished and does not include the time of speaking. E.g.: Geoffrey didn’t go skiing last year. ("last year") in the past. This period is expressed with a time expressionA word or group of words used in a particular situation. E.g.: Good morning, at six, on the sofa, however, the exact time may or may not be mentioned.