Like many of you, I am now running between different forums, at the same time. You guess correct, I am talking about English tense there.
I don't want to miss any chance of discussing about tenses, no matter how busy I now am.
Metamorfose was hitting the deceiving point and wrote: Some people here describe the Present Perfect as "an action that occurred in the past, but the time that it happened is not relevant or shown." that's deceiving for in (1) one can perfectly use the Past simple and yet not mention when it occurred.
(1) They won the match.
However, we didn't stay on the inseparable pair:
(1) They won the match.
(1b) They have won the match.
It was a very wise step to avoid the discussion. Perhaps achieving the avoidance was exactly what we wanted. Those academic papers from learners arguing we don't know about Present Perfect are because of this pair of examples, obviously.
Metal56 jumped to an totally unconcerned style of structure: a question that contains SINCE. We know what SINCE can do, and it even instantly quieted down further discussion over
the deceiving definition, as Metal56 seemed to have produced evidence to prove it is not so
deceiving. Now that nobody will claim we can use Simple Past to say the same with SINCE, the
deceiving definition can save its skin.
But what we weren't aware is, as Met56 has linked to <Perfect + SINCE>, a sentence containing both Present Perfect and a time Frame, we are linking it to Simple Present. Actually, even Simple Present can be sometimes fit for the
deceiving definition
"an action that occurred in the past, but the time that it happened is not relevant or shown":
(2) He stayed in Hong Kong (sometimes).
(2b) He has stayed in Hong Kong (sometimes).
(2c) He stays in Hong Kong (sometimes).
== All three can be fit for the
deceiving definition.
In 2c, Simple Present does mean his staying did occur in the past. Likewise, if you
are a teacher, the teaching does occur in the past sometimes, though
not finished now. If you
eat frog, your habit of eating does occur in the past, though the habit is
not finished now. Therefore, I guess Metamorfose should have enclosed the idea of
now-finished in the definition, so as to restrict the discussion only to Simple Past and Present Perfect.
As you all must now understand, as far as people admit there is a problem in seeing the different use between Simple Past and Present Perfect, I have noticed there is another problem between Simple Present and Present Perfect (2c and 2b above). As long as people are checking the 'meaning', rather than the time, of Present Perfect, there are the confusions. The reason is really very simple:
every case of happening or meaning must have its past, present, and future. Different tenses are just used to tell different kinds of time of the happening or meaning. There is no exceptional meaning or happening that is without time. Therefore, it is arbitrary for us to say Present Perfect expresses a meaning, such as a result, experience, current relevance, etc. We literally can use Present Perfect to express anything. More accurately, we can use any tense to say any meaning or happening. Different tenses tell different time.
Furthermore, I repeated, and have repeated, and am repeating, and will repeat this in the future:
Simply a statement "No, thanks. I have taken dinner" doesn't mean I don't take dinner anymore. Rather, Present Perfect is used to contrast with the time of your present request to go restaurant together. Therefore, to define just
I have taken dinner is of no avail. Tenses are thus further, most chiefly, used to tell the time relations between happenings. Simple Past is used to connect to another Simple Past, but Present Perfect isn't to another Present Perfect. Present Perfect actions describe finishes outside the time frame of Simple Past actions. Concrete examples are in the thread of "Highly Selected Examples".
Shun Tang
