Present Perfect and The Influence of Algorithms
A. We use the simple past with actions that happened and ended in the past. The time is specific or understood from context -I ate sushi last night -We saw a movie yesterday -I practiced karate when I was a child B. We use the present perfect for actions that happened before the present, sometime in the past, but we don't say when specifically -My mother has visited Mazatlan before -I haven't been to Tokyo -She has met Tom Cruise once When did the action happen? We don't know. We use the present perfect to describe life events. C. We also use the present perfect for actions that started in the past and continue in the present (unfinished actions) -I have worked in Hubbell for 5 years -We have studied English since 2012 -I have worked hard this year Here we emphasize time progress. Actions that have occurred for a period of time. Notice the difference: - I married my wife in 2010 (Simple past: action that happened in the past) - I have been married...