I want to know: Could a sentence in the present perfect tense has different meanings under different contexts? I don't really think so. It's like in every native english speaker's mind, in their concepts, there is only one answer for some kinds of typical sentences no matter what context is, since the context would also let you feel that way. I can give you two examples. I think they are typical sentences in the present perfect tense:1) When a person says: I have eaten a chicken. Even though you don't have context, you will think that it means he already ate it . That sentence has only this one meaning. You will not think that it means he ate it, and he is still eating it. Then If he gives you a context, I think the context would also let you feel that it means He already ate it. But if he tries to express that he is still eating it (the second meaning),then you must feel so weird that this person expressed wrongly. 2) I have never been to England. No context for you now. You must think it means I didn't go to England before, and now I am still not there; From past to now, I have never been there.  I think you don't really need context to understand the Use of this sentence.  However, If i give you a context. Suppose that we are both now in England, and i say to you: "This country is nice, I have never been here."  Then, you must feel so weird, because in your mind, "I have never been here" means .... (I already said above).  So you may correct me:"you need to say 'I have never been here BEFORE' ".  [I am not so sure about this example, because my teacher told me "I have never been to England" mean I didn't go there before. So i can say this sentence when I AM in England right now]   But i think you can get my point now? If you don't agree with my thought, then you mean a sentence (two sentences i gave above) has different meanings under different contexts? I hope you can solve my confusion.  Thanks a lot!

No.  In the examples provided by the original poster, the reference moment is now, not some moment in past time, for which you could've used had, as in:

Maple wrote:

How about using had on this occasion?? Suppose:  I'm in England now, and I want to say this is the first time for me to be in England. I would say: I had never been here before.

Maple,

You can say “I had never been to China before until my parents took me there on vacation two years ago”. The rule of thumb in using past perfect is that one must use a little logic to analyze the sequence of events. The structure must have 2 events which took place in the past and one must precede the other, and these events are no longer ongoing.

Here, aample structure is: 1) I had never gone to China all my life. (until)  2) my parent took me there two years ago. Please note, Often in reporting style writing, the writer presumes that the readers understand the contexts and omits the second event.

Example: If I were talking to someone about my past, I could say “I had never learned English as a Child. Omitted and presumed understood: when I lived in Hong Kong.

I hope I am not confusing you