 Hello class, welcome to this video where I will explain how the present perfect tense works. When is it used? It's used when the action has not yet finished. It's still going on or there's some results that are still going on. For example, I have played piano for two years. I have played means I started playing but it's still going on. I still play the piano. This is why I have to use the present perfect tense because it still has something to do with the present even though I started it in the past. How is it formed? It's formed by have or has plus the participle. This means in an example, I have waited. Waited is a participle or you have played. He has written. She has eaten. It has rained. We have practiced. You have cooked and they have visited. How does the question work? They have done their homework. If it's a question you have to invert. Instead of they have, have they done their homework? The negative. They have done their homework. They have not done their homework. You have to use the helping word not together with have or has. Situation with the word for. They have lived in Austria for 10 years. This is a time period for 10 years. It's long. Situation with for example, for years, two months, for a week, for two minutes. What about the word since? They have not eaten since this morning. This is a point in time. It's not a long time period. It's a point in time since this morning. For example, since Christmas, since 2015, since I was seven, or since I was a baby. I hope you have understood how the present perfect tense works. Bye now.