1.1) hasn't learned, 2) has done 3) have already watered 4) has just cleaned 5) has drawn
2.Polly has just performed her ballet dance. 2) Ron has prepared his costume yet. 3) the children have invited people to the concert yet. 4)Andry has just finished the poster.
1 These cups are dirty. 2 Those biscuits were tasty. 3 These hotels are very expensive but they're very nice. 4 There are children's playgrounds in the park. 5 Those are new supermarkets in our town. 6 They are delicious lemon pies for dessert. 7 They are nice cotton dresses for my niece. 8 These men are engineers. 9 Those women are my sisters. 10 These children are my sons. 11 Those geese are big... 12 These mice are white. 13 These men are doctors. 14 These women are my cousins. They are teachers 15 Those girls are my nieces.
Present Perfect используется для обозначения действия, совершившемся в прошлом, и это связано с настоящим, наличием какого-либо результата или последствий. И важен сам факт совершения действия, а не время.
1 Was she told the story by them? 2. What must be done about this by us? 3. What questions were asked by them?4. Have the curtains been changed by anyone yet? 5. Where was the car parked by them? 6. Will he be told about the accident by anyone? 7. Has that blackboard been dusted by anyone yet? 8. Who is my room being cleaned by?