Simple Past and Present Perfect

Uses

Simple Past	Present Perfect
Use the Simple Past to express the idea that an action started and finished at a specific time in the past. Sometimes, the speaker may not actually mention the specific time, but they do have one specific time in mind.	We normally use the Present Perfect when we want to talk about about something which happened in the past but is relevant now
The present perfect is used when the time period has NOT finished: I have seen three movies this week. (This week has not finished yet.)	The simple past is used when the time period HAS finished: I saw three movies last week. (Last week is finished.)
The present perfect is often used when giving recent news: Martin has crashed his car again. (This is new information.)	The simple past is used when giving older information: Martin crashed his car last year. (This is old information.)
The present perfect is used when the time is not specific: I have seen that movie already. (We don't know when.)	The simple past is used when the time is clear: I saw that movie on Thursday. (We know exactly when.)

Signal Words

Simple Past	Present Perfect Simple
§  yesterday §  ... ago §  in 1990 §  the other day §  last ...	§  just §  already §  up to now §  until now / till now §  ever §  (not) yet §  so far §  lately / recently

Exercise

http://www.ego4u.com/en/cram-up/grammar/simpas-preper/tests?test3

http://www.englishpage.com/verbpage/verbs5.htm

http://www.learnenglish.org.uk/CET/flashactivities/learnenglish-central-grammar-presperf-pastsimple.html

http://www.eclecticenglish.com/grammar/PresentPerfect1E.html

http://www.englishgrammarsecrets.com/presentperfectorpastsimple/menu.php

http://www.ego4u.com/en/cram-up/grammar/simpas-preper/exercises?ex07