GRAMMAR FOCUS:

Present Perfect Tense

Present Perfect Tense is used:
• To show actions completed in the immediate past (usually with JUST);
He has just left for the airport.
I have just finished my homework.

• To show past actions whose time is not mentioned and definite;
Have you read "Harry Potter"?
I have seen Japan.

• To define past events when we focus on their effect in the present than of the action itself;
Aslam has eaten all of the cake. (There isn't any left for me)
I have cut my finger. (and it is bleeding now)
I have done my homework. (now I am free)

• To show experiences of your life;
I have been to K-2.
I have jumped from an aeroplane.

• Present Perfect Tense is also used To express a situation (not action) that began in the past and continues to the present and it usually comes with since or for ;
(a) I have been here since seven o'clock.
(b) We have been here for two weeks.
(c) I have known him for many years.