GRAMMAR
Here is website which explains the difference between the PPS and PPC
This explanation shows how the present perfect simple = results and the present perfect continuous = action. At the bottom of the page, there are several excellent interactive exercises. Try to do a few of them.
7.2 Present Perfect - Experience smrt
Read the notes.
STRUCTURE
7-1 Singular and Plural Verbs smrt
7-2 Noun Quantifiers smrt
Read the notes.