present perfect - result or completion?

[keannu]

Most grammar books I've read always divided present perfect into four categories - result, completion, experience, continuity, but "Result" and "completion" are always confusing. I feel this kind of classification is artificial. For example, "I've just read one page" can be seen as "a result" instead of "completion" and vice versa for 1. I don't know how to tell the two and if it is meaningful. What do you think?

1.result
A : Can I use your cellphone?
B : Sorry, I've left it at home(So I don't have it now)

2.completion
A : Is that book interesting?
B : I don't know. I've just read one page.

 

[5jj]

. I don't know how to tell the two and if it is meaningful. What do you think?

I think that it is more important to understand what has been said/written than to worry about labelling.