1. She has just finished doing her home assignment.
2. They have already returned from the country. You can talk with them.
3. Unfortunately, we can't contact them. They haven't returned yet.
4. Has she ever worked in the rescue team?
5. He is quite old, but he has never seen the tornado.
6. We have stayed in the mountains for a month.
7. The city has changed greatly since last year.
8. I haven't written anything yet. Let me have a rest first.
9. We haven't met him since the earthquake.
10. She has been already shown on TV.