Положительные-
1.We have bought a new TV set.
2.The students have left the room.
3.The train has just arrived.
4.He has written about a hundred novels.
5.I have already bought that book.
отрицательные-
1.I have not written the letter.
2.I had not written the article.
3.I should not have written the test work.
4.She hasn't written the test yet.
5.He hasn't phoned this afternoon.