The Present Perfect is used to show a connection between the present and the past. The time of the action is not mentioned, and the outcome of the action is more important than the action itself. So..the action started in the past and continues in the present. E.g.: I have been to this place before. The Present Continuous tense is used for actions happening now or for an action that is unfinished. E.g. I am writing you a letter (I'm not finished and I'm doing it now). *the infinite tense is known as the Continuous tense