Ответ:
1. I have done my homework
2. Greta has walked her dog
3. Galina has been to the Crimea (Galina has travelled to the Crimea)
4. The alpinists have climbed the volcano
5. Kari has skied down a mountain
6. I have ridden a camel
7. Carly and Sam have swum with dolphins
Объяснение:
3. been to - если она вернулась, travelled to (она только приехала туда). В задании просят результат, поэтому been to подходит лучше