Ответ:
Task 1.
1. We have walked 10 km.
2. We have been walking for 3 hours.
3. She has slept on every bed in this house.
4. She has been sleeping since 10 o'clock.
5. That boy hasn't eaten anything this morning.
6. That boy has been eating ice cream all morning.
7. The students have been working really well this term.
8. The students have been writing 5 essays so far.
9. I've been cleaning the bathroom all day, and now I feel exhausted.
10. I have cleaned the bathroom twice this week.
Task 2.
1. I have been looking for hours.
2. How many paintings have you sold so far?
3. The professor has answered about 100 questions.
4. John has known Cynthia since primary school.
5. I've seen most of his paintings.
6. How long have you been waiting for me?
7. How many art galleries has he visited today?
8. How long have you had this painting?
9. Has she finished her essay? No, she has been writing it all day.
10. ... Have you run?
11. I have been trying to call you since morning.
12. I have lost my phone.
13. The robber has returned the money to the bank.