1. http://estudiaingles-videos.blogspot.com/2008/03/planning-vacation-planear-vacaciones-en.html

2.  We form the Present Perfect with have and the past participle  have/has + past participle  has: 3rd person singular (he, she, it)  have: all other forms  past participle: - regular verbs: infinitive + -ed - irregular verbs: 3rd column of the table of the irregular verbs Example sentences:  Affirmative: I’ve done my homework.  Negative: I haven't done my homework.  Question: have you done your homework?

3.  The present perfect is often used for an action which started at some time in the past, and still continues now. Example:  She has worked at the University since 1994. (She started working at the University in 1994, and she's still working there now.)

4.  Sometimes, it's important to say that something happened (or didn't happen), but it's not important when it happened. Example:  Have you ever been to Germany? (It doesn't matter when you went -- I just want to know whether you have been there or not.)

5.  In this case, the action happened at some time in the past, but the effect of the action is still important now. Example:  Present perfect She's broken her arm. The arm is still injured.  Simple past She broke her arm. The arm is probably OK by now.

6.  PRESENT PERFECT + for, since When talking about the length of time (duration), we use the present perfect with for + a period of time. for six years, for a week, for a month, for hours, for two hours.  Example: I have worked here for five years.

7.  When talking about a starting point, we use the present perfect with Since + a point in time: since this morning, since last week, since yesterday, since I was 12, since Friday, since 6 o'clock.  Example: I have lived here since 1998.

8.  http://web2.uvcs.uvic.ca/elc/studyzone/410 /grammar/pperf2.htm http://web2.uvcs.uvic.ca/elc/studyzone/410 /grammar/pperf2.htm  http://web2.uvcs.uvic.ca/elc/studyzone/330 /grammar/upperf1.htm http://web2.uvcs.uvic.ca/elc/studyzone/330 /grammar/upperf1.htm  http://www.ego4u.com/en/cram- up/grammar/present-perfect-simple http://www.ego4u.com/en/cram- up/grammar/present-perfect-simple