| PRESENT PERFECT | PAST SIMPLE |
when the time period has NOT FINISHED: I have read two books this week. | when the time period HAS FINISHED: I read two books last week. |
when giving RECENT NEWS: Jim has fallen off his bike again. | when giving OLDER INFORMATION: Jim fell off his bike last summer. |
when the time is NOT SPECIFIC : I have already seen that documentary. | when the time IS SAID : I saw that documentary on Thursday |
| with FOR / SINCE |
when the actions have NOT FINISHED YET : I have lived in London for three years. (I still live in London.) | when the actions have ALREADY FINISHED : I lived in London for three years. (I don't live in London now.) |