1. Tom has seen this film before.

2. I have finished my exercise already.

3. They have lived here since 1990.

4. My father has just washed his car.

5. The students have discussed the question recently.

6. Mary has never been to Ha Noi.

7. We have known each other for 5 years.

8. So far we have learnt five lessons.

9. We have been pen pals for a long time.

10. They have stayed here since last week.