Hi Rafaela, The past simple is for things in the past with a clear 'when,' while the present perfect is for things from the past that matter now, without saying exactly 'when'. EXAMPLES: 1. I visited Madrid last summer." (This tells us exactly when you went to Madrid – last summer.) 2. I have been to Madrid." (This focuses on the fact that you went to Madrid without specifying when, and it matters because it's something you can talk about now.) 3. I saw Sara last week. (You saw Sara at a specific time in the past, which was last week.) 4. I have seen Sara this week. (At some point during the current week, but it's not specified exactly when.) 5. She travelled to Spain last summer. (This tells us the specific time when she went to Spain, which was last summer.) 6. She has travelled to Spain before. (The focus is on the experience, not a specific time.) 7. I visited my grandparents on Saturday. (This specifies a particular time in the past when the visit happened, which was Saturday.) 8. I have visited my grandparents recently. (The exact time is not mentioned, but it's connected to the present.)