В отрицательных предложениях в Perfect употребляем yet, который всегда ставим в конце предложения.
1.Ann hasn't watered the flowers yet.
2.Mum hasn't gone to her work yet.
3.I haven't seen this film yet.
4.We haven't taken the bus yet.
5.Bob hasn't entered the shop yet.
6.They haven't read this book yet.
7.The children haven't made a present for their mother yet.