A. The Present perfect tense is formed by using the present tense of the auxiliary have/has and the past participle of verb :
|+||I/You/They/We have||worked since 2002|
|He/She/It has||been there for 2 month|
|–||I/You/They We have not (haven’t)||worked since 2002|
|He/She/It has not (hasn’t)||been there for 2 months|
|?||Have I/You/They/We||worked since 2002|
|Has he/she/it||been there for 2 months|
Short answer :
Yes, I/You/They we have No, I/You/They we haven’t
Yes, he/she/it has No, he/she/it hasn’t
B. We use the present perfect to talk about action that began in the past and continue in the present
She’s worked her for years (she still works here)
C. We use the present perfect to talk about a present situation in which is a result of something that happened at an unspecified time in the past. Therefore we do not use specific time expression such as yesterday, last week, etc.
I have given your report to the director (I gave him your report and he has it now)
I have sent them the samples that they wanted (I sent them. They are in the post now).
Sumber : Hand Out English Professional I Stie PGRI DEWANTARA JOMBANG by Ida Setyawati, S.Pd, M.Pd