PRESENT PERFECT SIMPLE

We use de Present Perfect Simple to talk about the action or experience in the general past, the specific time is not important or is not know.

AFIRMATIVE FORM: Estructure:

Subject + Auxiliary + Past Participe + Complement.

Example:

He/She/it/ Has met some interesting people.
I/ You/We/ They Have had lost of other jobs.

NEGATIVE FORM: Estructure.

Subject + Auiliary + not + Past Participe + Complement.

Example:

He/She/ it has not/ hasn´t/ been to the USA before.
I/ You/We/They have not/ haven´t has a holiday.

INTERROGATIVE FORM: Estructure:


Auxiliary + Subject + Past Participe + Complement.
Example:

Has He/She/It listened to something?
Have I/ You/We/They sat somewhere?

http://www.ego4u.com/en/cram-up/grammar/present-perfect-simple/exercises?04
http://web2.uvcs.uvic.ca/elc/studyzone/410/grammar/ppvpast.htm

http://www.authorstream.com/Presentation/bbogage-14003-simple-past-vs-present-perfect-tense-education-ppt-powerpoint/