Present Perfect Simple

Look at this sentence:

a) I haven't finished my test yet!

What does it mean?
Which are the elements that you can see in the sentence?

Now, have a look at this:

b) She has been in Sydney recently.

What does it mean?


If you care to pay attention, you will see that in situation a) you have began your test at 10 o'clock and it's 10.50 and haven't finished it yet. Meaning that you began an action in the past that came up to the present moment.

In sentence b) you refer to an action that occured "somewhere" in the past. You give emphasis to What happen and to When it happened.

Structure:

have/has + past participle

Time expression:
already, yet, just, since, for, never, ever...

What's the difference between Present Perfect and Past Simple?

In the Past Simple you know when something happens.
You can have time expressions such as these: a year ago, last month/year/weekend, yesterday....

Time to work!

Present Perfect:

http://web2.uvcs.uvic.ca/elc/studyzone/410/grammar/pperf1.htm 
http://web2.uvcs.uvic.ca/elc/studyzone/410/grammar/pperf3.htm
http://www.ego4u.com/en/cram-up/grammar/present-perfect-simple/exercises

Present Perfect vs Past Simple:

http://web2.uvcs.uvic.ca/elc/studyzone/410/grammar/ppvpast2.htm
http://web2.uvcs.uvic.ca/elc/studyzone/410/grammar/ppvpast3.htm
http://www.englishpage.com/verbpage/verbs5.htm