Present perfect simple is used: - To express an action that began in the past and continues to the present: I've lived here since 1999. - To express an action that has already happened and have a relation with something in the present: I have bought a car. Present perfect continuous is used: - To express an activity which continues to the present: It has been raining for days. - To refer to an activity with a result in the present: I'm hot because I've been running.

Sara's answer is correct. We often use "ever" and "never" along with have and has and the passive participle. We call it Perfect because it started perfectly in the past and continued without interruption, or mistakes, perfectly in the past and bingo! Welcome to the present. Often "have" is reduced to 've when spoken so it's easy to miss and confuse it with the simple past, especially the regular verbs. Good Q!

The Present Perfect is being used for different purposes: 1- To express an act that you have started in the past and doesn't come to an end yet. e.g : "I have worked for this company for 3 years." It means that I am working there during the last 3 years, I still work there and didn't leave it. But if you said " I worked for this company for 3 years." Here the meaning is that I worked for this company for three years in the past and now I am no longer there. 2- To express an action that happened in the past and has an impact on the present time.e.g : " I have forgot my key." It means that I am not able to open the door now. But " I forgot my key." It may be ended long time ago and now I have another key. 3- To Talk about experience to express an action that you made in the past and the exact time when you made it is unknown. e.g : " I have seen China Great Wall before." but " I saw China Great Wall when I was there last year." 4- To describe an action that is happening for the first time. e.g: "I have never met such an intelligent woman." It means This is my first time to see an intelligent girl like her. 5- Take care of the difference between (went to ...Vs. have been to...) " I went to China." means that I am still there now. " I have been to China." means that this visit has finished and I am home now.

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Present perfect indicates an activity that has been completed in a recent past in an unspecified time. Example:- I have done my work <impact on present> Differences:- 1) simple past:- To show time * I have eaten my breakfast.(I am not hungry) 2) Present perfect:- without showing time <impact on present> *I ate my breakfast at 7 o'clock. (when did you eat your breakfast)