past perfect/present perfect

[bayan said]

Dear sir,
Thank you very much for your reply,what about the present perfect message?
you only answered 1 question from point2.would you please answer all the questions?(including the questions of point1).well here are some questions:
1- I've read"some times the speaker mayn't mention a specific time but they do have one in mind"my question:how do we know that the speaker has that specific time in mind?(when using simple past)
2- I've read this phrase after a game of cards: "I didn't win because I'm the number one duelist in the world,I won
because you stink".my questions here:1-why is"the"used befor "number"?-2- what does "stink"mean here?
3- I've read in"Time machine":"you can't get away from the present moment~
No sir,that's just where you're wrong.From birth to death we're moving steadily along in time just as we'd mone if we...."why did the speaker say"from birth to death we're moving"instead of "from birth to death we move"since this is a fact?
4- I've read this note"Dear Lusy,we're shopping in town.Lis has been studying for hours & has gone out for a walk we'll be back at8"my question:why did the speaker use present perfect progressive with the verb"study"instead of saying"had studied"since the verb is finished?
5- What's the difference between "just& only?
all the best..

[RonBee]

Dear sir,
2- I've read this phrase after a game of cards: "I didn't win because I'm the number one duelist in the world,I won
because you stink".my questions here:1-why is"the"used befor "number"?-2- what does "stink"mean here?

There is, presumably, only one number one duelist in the world, thus it is the number one duelist and not a number one duelist. "You stink" means "You are not very good".

5- What's the difference between "just& only?
all the best..

It depends on context. Often there is no difference. Example:

He shouldn't be giving advice. He is just a student.
He shouldn't be giving advice. He is only a student.

In those sentences just and only mean the same thing.

~R